250 New Gateway to Computer Science Book-8 like Science, Mathematics, English, Computer and other subject is available by which students can learn easily. The concept of distance learning is also based on multimedia. Universities and colleges can provide multimedia CD and DVD to their students for the learning as a studying material. Multimedia has the ability to accommodate different learning styles by integrating text, picture, audio, video, etc. Health The flow of information related to health service can be exchanged with the help of multimedia. It is mainly used to provide telemedicine services in the remote area. Multimedia tools are also used to provide health services all over the world with the help of video conference. Multimedia technology and devices are used to diagnosis the diseases. Multimedia technology can be used to transform the information about the health services and produce public awareness programs which can be broadcasts from different media. Entertainment These days, without multimedia, entertainment is almost impossible. With the help of multimedia, we can record music; create a video, movies and animated documents. 3D, 8D, 16D types of movies, digital movies, and animated cartoon films are possible because of the use of multimedia. Business To create and promote business and products we can use multimedia. We can add animation in the advertisement to make it more effective and interesting. For the marketing strategy, the use of multimedia in business is essential. Text, video, animation, audio, etc. are the elements of multimedia. Graphic is a visual multimedia element which represent such as a photo, illustration, 3D or diagram. Animation is a visual technique that provides the illusion of motion by displaying a collection of images in rapid sequence. The use of multimedia in education can make more changes in the teaching and learning activities. Multimedia technology can be used to transform the information about health services and produce public awareness programs in health sector. We can add animation in the advertisement to make it more effective and interesting. Quick Learn
251 New Gateway to Computer Science Book-8 1. Fill in the blanks with suitable words. a. ……………… refers to interactive, computer-based applications that allow people to communicate ideas and information with digital and print elements. b. A ………………………. file can be any computer file that plays audio and video, audio only, or video only. c. ………………Player is a media player and media library application developed by Microsoft. d. ………… is a visual multimedia element which represent photo, illustration, 3D or diagram. e. The use of ……………………. in education can make more changes in the teaching and learning activities. f. ………………….. can be used to transform the information about the health services and produce public awareness programs in health sector. 2. State whether the following statements are true or false. a. Multimedia technology applies interactive computer elements, such as graphics, text, video, sound, and animation to deliver a message. b. Multimedia software is a software that is capable of playing or recording audio files or playing or recording video files. c. Text, video, animation, audio, etc. are the application of multimedia. d. Audio is a visual technique that provides the illusion of motion by displaying a collection of images in rapid sequence. e. We can add animation in the advertisement to make it more effective and interesting. 3. Write very short answer to the following questions. a. Name any two elements of multimedia. b. Write any two popular application areas of multimedia. c. Is audio required in multimedia? EXERCISE
252 New Gateway to Computer Science Book-8 d. Write any one popular multimedia player software. e. What method of teaching is effective in the classroom for learning process? 4. Write short answer to the following questions. a. Define multimedia. What are the elements of multimedia? b. What are the advantages and disadvantages of using multimedia? c. What is a multimedia software? Name some popular multimedia software. d. What are the components required for multimedia? e. What are the application areas of multimedia? Explain one of them. 5. Write long answer to the following question. a. Explain in details about the elements of multimedia. b. What is the role of multimedia in education and entertainment? Explain in detail. • Divide your class in various groups and conduct a presentation on the following topics. • Application areas of multimedia. • Role of multimedia in education. • Latest multimedia technology for the entertainment. Lab Activities
Read a,b,c Print c Print a Start No No No Yes Yes Yes Stop If a > b If b > c If a > c Concept of Computer Programming Unit 5 Chapter 18 Chapter 19 Chapter 20 Program Designing Tools and Techniques Fundamental Knowledge of Programming Computer Programming in QBASIC Elements of QBASIC statements Specification Grid Practical Time Model Question Inside the Unit
254 New Gateway to Computer Science Book-8 Introduction Program Design tools are the tools used to develop a program. During designing a program, different tools are required to solve several problems. Programming tool is a computer program that software developers use to create, debug and maintain programs and applications. The most basic tools are a source code editor and a compiler or interpreter, which are used universally and continuously. A programming tool may be any software program or utility that helps software developers or programmers in creating, editing, debugging, maintaining and/or performing any programming or developing-specific task. A programming tool is also known as a software development tool. Tools for program designing A programmer can use the given tools to design a program which we are going to discuss below. Algorithm We have to use different steps to solve the problems. An algorithm is a set of instructions designed to perform a specific task. We can define algorithm as a step by step procedure to solve a given problem in a finite number of steps. The steps which we are writing in algorithm should be in a proper sequential order. While preparing an algorithm, we should identify what should be the input, process, output and storage. Program Designing Tools and Techniques 18 Chapter This chapter covers the following topics: Expected Competency At the end of this unit, students willbe able to: • identify the various program designing tools. • write the features of algorithm. • tell about the types of flow charts. • define the pscudocode.
255 New Gateway to Computer Science Book-8 Features of algorithm The entire algorithm should begin with ‘START’ and end with ‘STOP’ words. The words you are going to write for the algorithm should be clear and understandable. It helps to write and develop a program. Never use any programming code or language to write the algorithm. The final algorithm should produce actual result. Some examples of algorithm Write an algorithm to calculate simple interest. Step 1 : Start Step 2 : Input the principal amount and store it in variable P. Step 3 : Input the time taken and store it in variable T. Step 4 : Input the rate percentage and store it in variable R. Step 5 : Calculate Interest with formula, interest = (PXTXR)/100 Step 6 : Display the value of interest Step 7 :Stop Write an algorithm to add two numbers entered by user. Step 1: Start Step 2: Declare variables num1, num2 and sum. Step 3: Read values num1 and num2. Step 4: Add num1 and num2 and assign the result to sum as sum = num1+num2 Step 5: Display sum Step 6: Stop Write an algorithm to find out the area of a room. Step 1 : Start Step 2 : Input the length of a room and store it in variable L. Step 3 : Input the breadth of a room and store it in variable B Step 5 : Calculate the area with formula, Area = (LXB)/100 Step 6 : Display the area of room. Step 7 :Stop
256 New Gateway to Computer Science Book-8 Flowchart Flowcharts use special shapes or symbols representing different types of actions or steps in a programming process. It is a diagrammatically representation of an algorithm. Flowcharts are commonly used in developing business plans, designing algorithms and determining troubleshooting steps. Many software programs are available to design flowcharts. Some of the commonly used software programs are Smart Draw and Visio. Flowcharts are useful to: collect data about a particular process. understand the relationship among different process steps. help in decision making. show the structure of a process. measure the performance of a process. highlight important steps and eliminate the unnecessary steps. track the process flow. Rules for drawing flowcharts. Never forget to use start and ending symbols at the beginning and ending of flowchart. Do not forget to analyse the input, process, storage and output. There should be list of activities inside each symbol. Do not cross the flow lines with each other symbols. It should express all sections like input, process, logical and output. It should not be any programming language oriented. Always use connector if a flowchart is not sufficient in a page. Program Design tools are the tools used to develop a program. Programming tool is a computer program that software developers use to create, debug and maintain programs and applications. A programming tool is also known as a software development tool. Algorithm is a step by step procedure to solve a given problem in a finite number of steps. Flowchart is a diagrammatically representation of an algorithm. Quick Learn
257 New Gateway to Computer Science Book-8 Types of flow chart There are two types of flowcharts which are explained below. System flowchart System flowcharts are a way of displaying how data flows in a system and how decisions are made to control events. This is the most common type of flowchart. It is used to show the logical flow of the process and includes decisions, flows of control, data stores and documents. Program flowchart Program flowchart is a diagram which uses a set of standard graphic symbols to represent the sequence of coded instructions fed into a computer, enabling it to perform specified logical and arithmetical operations. It is a tool to improve work efficiency. There are four basic symbols in program flowchart; start, process, decision and end. Each symbol represents a piece of the code written for the program. S.N Symbols name Description 1. Start / Stop It indicates the starting and ending of flowcharts. 2. Input / Output It indicates input or output operations. 3. Processing It indicates any calculations or manipulations. 4. Decisions It is used to show the steps involving comparison and decision making. 5. Flow lines It shows the flow of control in a program. 6. Connectors It indicates a junction point at which flowchart joins with a part of flowchart to another place or part. 7. Comment It is used to write the comments about flowchart symbol.
258 New Gateway to Computer Science Book-8 Some examples of flowcharts Draw a flowchart to find out the sum of any two numbers. Draw End Read A Read B Print Sum Sum=A+B Draw a flowchart for finding the smallest of three numbers. Read a,b,c Print b smallest Print c Print a Start No No No Yes Yes Yes Stop If a > b If b > c If a > c
259 New Gateway to Computer Science Book-8 Pseudocode Pseudocode is a simple way of writing programming code in English. Pseudocode is not actual programming language. So, it cannot be compiled into an executable program. It uses short terms or simple English language syntaxes to write code for programs before it is actually converted into a specific programming language. This is done to identify top level flow errors and understand the programming data flows that the final program is going to use. Examples of Pseudocode Write a pseudocode to add 2 numbers together and then display the result. Start Program Enter two numbers, A, B Add the numbers together = A + B Display the Sum End Program Write a pseudocode to calculate the area of a rectangle. Start Program Get the length, l, and width, w Compute the area = l*w Display the area End Program There are two types of flowchart. They are program flowchart and system flowchart. System flowcharts are the way of displaying how data flows in a system and how decisions are made to control events. Program flowchart is a diagram which uses a set of standard graphic symbols to represent a sequence of coded instructions. There are four basic symbols in program flowchart. They are start, process, decision and end. Pseudocode is a simple way of writing programming code in English. Pseudocode is not a programming language. Quick Learn
260 New Gateway to Computer Science Book-8 1. Fill in the blanks with suitable words. a. Program ………. are the tools used to develop a program. b. A …………….. tool is also known as a software development tool. c. ……………. is a diagrammatically representation of an algorithm. d. There are two types of flowchart. They are program flowchart and …………… flowchart. e. ………………… is a diagram which uses a set of standard graphic symbols to represent the sequence of coded instructions. f. …………….. is not a programming language. 2. State whether the following statements are true or false. a. Programming tool is a computer program that software developers use to create, debug and maintain programs and applications. b. Flowchart is a step by step procedure to solve a given problem in a finite number of steps. c. System flowcharts are the way of displaying how data flows in a system and how decisions are made to control events. d. Pseudocode is a simple way of writing programming code in English. e. There are three basic symbols in program flowchart they are start, process, decision and end. 3. Write very short answer to the following questions. a. What is the use of program design tools? b. Write the name of any two programming languages that you know. c. What is another name for the programming tool? d. Name any two types of flowcharts. e. Name any two shapes that are used in flowchart. f. Does an algorithm use symbols in steps? EXERCISE
261 New Gateway to Computer Science Book-8 4. Write short answer to the following questions. a. Define algorithm and flowchart. b. Write down the features of an algorithm. c. What are the uses of flowchart? d. Draw various symbols used by flowchart. e. What is a pseudocode? Write a pseudocode to calculate the area of rectangle. 5. Write long answer to the following questions. a. Explain the rules for drawing flowchart. What are the types of flowchart? Explain them. b. Draw a flowchart to calculate the simple interest and amount. c. Draw a flowchart to find the area of a triangle. Project Work & Activity • Prepare a chart with the symbols used by flowchart and submit to your teacher.
262 New Gateway to Computer Science Book-8 Introduction Today, most people do not need to know how a computer works. Most people can simply turn on a computer or a mobile phone and point at some little graphical object on the display, click a button or swipe a finger or both, and the computer does something. But, since we are going to learn how to write computer programs, you need to know about how a computer works. Basically, writing software (computer programs) involves describing processes, procedures; it involves the authoring of algorithms about which we learnt little in previous classes. A computer does not understand any languages as human. Programming language is needed to write a computer program. It is an artificial language that is used to communicate between computer hardware and user. We can use the three different languages to write the computer programs. They are machine language, assembly language and high level language. Among the three languages these days we are using high level languages to write the computer programs. Types of computer language Machine level language This language can be understood by the computer only. It is also called as the first generation language. Writing program in this language is very difficult because these are closer to machine but not a user. Machine level language is sometimes called a machine code or object code. It is a collection of binary digits or bits that the computer reads and interprets. Fundamental Knowledge of 19 Computer Programming Chapter This chapter covers the following topics: Expected Competency At the end of this unit, students will be able to: • define computer language with its types. • explain the advantages and disadvantages of programming langauages.
263 New Gateway to Computer Science Book-8 Advantages of machine language It can be directly understood by the machine. Program of machine language runs very fast Translation program is not required for the CPU. It uses less memory so it can be used in each type of machine. Disadvantages of machine language It is very difficult to program in machine language. The programmer has to know details of hardware to write program. The programmer has to remember a lot of codes to write a program It is difficult to debug the program. Assembly Language It is a low-level programming language used to interface with computer hardware. Assembly language uses structured commands as replacements for numbers. Only assembler can be used to translate the assembly language into machine level language and vice versa. An assembly language is the most basic programming language available for any processor. With assembly language, a programmer works only with operations that are implemented directly on the physical CPU. Assembly languages have the same structure and set of commands as machine languages, but they enable a programmer to use names instead of numbers. Advantages of Assembly Language Memory efficient. Programs written in machine language are replaceable by mnemonics which are easier to remember. Faster in speed. Easy to make insertions and deletions. Requires fewer instructions to accomplish the same result. Disadvantages of Assembly Language Long programs written in such languages cannot be executed on small sized computers. It takes lots of time to code or write the program. It is more complex in nature. Difficult to remember the syntax. Lack of portability of program between the computers.
264 New Gateway to Computer Science Book-8 High Level language High level languages are closer to human language. A machine cannot understand any type of high level language. A translator like compiler and interpreter can be used to translate the language from high level language to machine level language and vice versa. The programming style and context is easier to learn and implement in high level language than low-level languages. BASIC, PASCAL, FORTRAN, C/C++, HTML, JAVA, etc. are the examples of high level language. Advantages of high level language High level languages are closer to human language. It is very easy to understand. It does not depend upon a machine. It is very easy to modify. Disadvantages of high level language It cannot be understood by the machine. It does not execute directly on the computer system. Language translator is essential to convert the high level language into machine code. More memory is needed to work with programs. A computer does not understand any languages as human. Programming language is needed to write a computer program. We can use the three different languages to write the computer programs they are machine language, assembly language and high level language. Machine level language can be understood by the machine only. Machine level language also called as machine code or object code. Assembly Language is a low-level programming language used to interface with computer hardware. Assembly languages have the same structure and set of commands as machine languages, but they enable a programmer to use names instead of numbers. High level languages are closer to human language. A translator like compiler and interpreter can be used to translate the language from high level language to machine level language and vice versa. BASIC, PASCAL, FORTRAN, C/C++, HTML, JAVA, etc. are the examples of high level language. Quick Learn
265 New Gateway to Computer Science Book-8 1. Fill in the blanks with suitable words. a. ……………….. is needed to write a computer program. b. …………………. level language can be understood by the machine only. c. ……………language is a low-level programming language used to interface with computer hardware. d. High level languages are closer to ……………… language. e. BASIC, PASCAL, FORTRAN, C/C++, HTML, JAVA, etc. are the examples of ………... 2. State whether the following statements are true or false. a. A computer does not understand any languages as human. b. Machine language, assembly language and high level language are the three types of programming language. c. Machine level language is also called as machine code or object code. d. Machine languages have the same structure and set of commands as machine languages, but they enable a programmer to use names instead of numbers. e. A translator like compiler and interpreter can be used to translate the language from high level language to machine level language and vice versa. 3. Write very short answer to the following questions. a. What is the name of language that can be understood by the machine only? b. Name any two high level languages. c. Name the high level language that you know. d. Is assembly language a high level language? e. Which of the computer language is also called object code? EXERCISE
266 New Gateway to Computer Science Book-8 4 Write short answer to the following questions. a. What is a programming language? Write down the types of computer languages. b. What are the advantages and disadvantages of machine languages? c. What is an assembly language? Write its advantages and disadvantages. d. Define high level language with its examples. e. Mention the advantages and disadvantages of high level languages. 5. Write long answer to the following question. a. Explain the role of programming language in computer system. Project Work & Activity • Make a list of any 10 programming language in A4 paper with the help of the internet and submit to your teacher.
267 New Gateway to Computer Science Book-8 Introduction QBASIC stands for Quick Beginners All-purpose Symbolic Instruction Code. It is the most popular high level programming language. QBASIC is the advanced form of BASIC program. The BASIC program was developed by John George Kemeny and Thomas Eugene in 1964 AD in USA. This language is quite simple to understand and has been adopted by most of the microcomputers. Features of QBASIC It is very easy to understanding and writing the programs. It has menu so that we can use QBAIC menu to perform various tasks easily. It is very easy to debug the programs. It is used for both scientific and commercial applications. Starting QBASIC Boot your computer system. Open the QBASIC folder location. Computer Programming in 20 QBASIC Chapter This chapter covers the following topics: Expected Competency At the end of this unit, students will be able to: • define QBASIC with its features. • tell the elements of QBASIC. • identify the types of operators. • explain various QUBASIC statements. • describe QUBASIC looping structure.
268 New Gateway to Computer Science Book-8 Double click on exe file of QBASIC. Now, you can see the QBASIC screen as below. Press Esc key to remove the welcome dialogue box and start working on QBASIC. Elements of QBASIC programming Character Set A set of characters that are allowed to use in QBASIC is known as the QBASIC Character Set. The QBASIC Character Set consists of alphabets (both small and capital), numbers (0 to 9) and special characters. These special characters have their own meaning and functions. QBASIC has the character set consisting of the following elements: Alphabets: A, B, C,....Z Digits: 0, 1, 2........,9 and Special characters: + - * / ( ) . , $ ; ,: ,= ,> ,< , ^ etc. Variables To store data in the computer, location are used. To locate or naming the address variables are used. Variable is a symbolic name that is used to store data (numbers, text, string, special characters, etc.) in the computer memory. During the program execution, the value of a variable is assigned to the computer memory. The following are the types of variables. Numeric Variable String Variable
269 New Gateway to Computer Science Book-8 Numeric Variable Numeric Variable is a symbolic name which is used to store only the numeric data. To declare numeric variable, the characters A-Z, a-z, string, special characters are used. For example x=20 Salary = 25000 a=5 Age = 12 A=13.5 B=25 SUM=A+B Types of Numeric variables Types of variable The number/character that it can hold Example Integer A whole number between -32,768 and 32,767 A% Long Integer A whole number between -2,147,483,648 and +2,147,483,648 A& Single precision Number from -3.37X10^38 to 3.37 X 10^38 A! Double precision Number from -1.67X10^308 to 1.67X10^308 A# String O to 32,767characters A$ String Variable String Variable is a symbolic name which is used to store text, text with numbers. $ sign is used at the end of string variable. The value of the string variable is stored in double quotation marks “ “. The following are the example to store string variable. N$ = “I am Dinesh Adhikari.” A$ = “I am from Dhading.” In the above example, N$, A$ are the string variables which store the value “I am Dinesh Adhikari.” and “I am from Dhading.” Rules for writing the variable name Variable name can be up to 40 characters. Do not use space between the names of variables. The name of variable always starts from alphabet and can follow by numbers. Never use QBASIC reserved words as a name of variables like CLS, INPUT, CLS, PRINT, etc.
270 New Gateway to Computer Science Book-8 Constants Constant is an identifier whose value does not change during the program execution. The value of constant is fixed value which is used in the program. There are two types of constants that we are going to discuss below. Numeric Constants. String Constants. Numeric Constants Numeric constant consists of a sequence of digits with or without decimal value. Numeric constant is a numeric value which is used in program. In numeric constant comma and blank space are not allowed to use. Let’s see an example. ADD = 20 + 10 In the above example, 20 and 10 are the numeric constants. String Constants: String constant is a string value which is used in program. In other words, it is the collection of numbers or texts or text with numbers followed by the $ sign. In string constant, we can use comma and blank spaces. Let’s see an example. D$=”Pravash” A$=”NeelakanthaDhading” QBASIC is the most popular high level programming language. QBASIC was developed by John George Kemeny and Thomas Eugene in 1964 AD in USA. The elements of QBASIC programming are character set, variables, constants, etc. A set of characters that are allowed to use in QBASIC is known as the QBASIC Character Set. The QBASIC Character Set consists of alphabets, numbers and some special characters. Variable is a symbolic name that is used to store data in the computer’s memory. Numeric and string are the two types of variables. The value of constant is fixed which is used in the program. Numeric constant consists of a sequence of digits with or without decimal value. String constant is a string value which is used in program Quick Learn
271 New Gateway to Computer Science Book-8 Operators and Operands Operators are the sign or symbols that are used to do mathematical calculations like addition, subtraction, multiplication and division. There are four types of operators in QBASIC. They are Arithmetic Operators, Relational Operators, Logical Operators and String Operator. Operands are the variables or constant values on which the operation is done. For example in expression [a + b], + is operator and ‘a’ and ‘b’ are operand. The whole expression [a + b] is called as the operations. Types of operators Arithmetic Operators Arithmetic Operators are used to perform mathematical calculations like addition, subtraction, division, multiplication and exponential. The following table shows arithmetic operators used in QBASIC. Operation Operator Examples Output Addition + 20 + 30 50 Subtraction - 45-10 35 Multiplication * 6*10 60 Floating-point Division / 10/2 5 Integer Division \ 13\2 6 Modular Division MOD 15 MOD 7 1 Exponential ^ 3^3 27 Relational Operators Relational Operators are used to compare the value of variables. A comparison of string data with numeric data cannot be done. The comparison of string data is done on the basis of ASCII value. The result of comparison is either true (1) or false (0).The following table shows the relational operators used in QBASIC. Relation Operator (Sign) Examples Equal to = A = B Greater than > A>B Less than < A<B Greater than or equal to >= A>=B Less than or equal to <= A<=B Not equal to <> A<> B
272 New Gateway to Computer Science Book-8 Logical Operators Logical Operators combine two or more relational expressions to evaluate a single value as True or False. The result of evaluation is used to make decisions about the program flow. The AND, OR and NOT are the commonly used logical operators. AND Operator AND operator returns ‘True’ when all the results returned from individual relational expressions are ‘True’. Otherwise it returns, ‘False’. The AND Truth Table is given below. Truth Table for AND operator INPUT (A) INPUT (B) Output (A and B) T F F T T T F F F F T F OR Operator: OR Operator returns ‘True’ if one of the relational expressions returns ‘True’. If all the relational expressions returns ‘False’, then only the result will be ‘False’. Truth Table for OR operator INPUT (A) INPUT (B) Output (A OR B) T F T T T T F F F F T T NOT Operator: NOT Operator operates on one operand and returns ‘True’ if the logical operation returns ‘False’. The NOT truth table is as given below. Truth Table for NOT operator INPUT (A) Output (NOT A) T F F T
273 New Gateway to Computer Science Book-8 Expression An expression can be a string, or numeric constant, a variable or a combination of constants, variables with operators which return a single value. We can write algebraic expression in QBASIC expression as given below. Algebraic Expression QBASIC expression 3(AB + BC) 3*(A*B + B*C) ab bc (a*b) / (b*c) A2 + B2 A^2 + B^2 A = 2h (L+B) A = 2*h *(L+B) Statements A statement is a computer instruction written in a source language, such as QBASIC, which is converted into one or more machine code instructions by a compiler. The commonly used QBASIC statements are: LET, PRINT, INPUT, CLS, END and REM in QBASIC which are described below. There are two types of flowcharts. They are program flowchart and system flowchart. Operators are the sign or symbols that are used to do mathematical calculations like addition, subtraction, multiplication and division. Logical Operators combine two or more relational expressions to evaluate a single value as True or False. An expression can be a string, or numeric constant, a variable or a combination of constants, variables with operators which return a single value. A statement is a computer instruction written in a source language, such as QBASIC, which is converted into one or more machine code instructions by a compiler. Quick Learn
274 New Gateway to Computer Science Book-8 Types of QBASIC Statements LET statement LET is an assignment statement. It is used to assign the value to a variable. LET is an optional statement i.e. without using LET statement we can assign the value to a variable. The data type must match with the variable type otherwise type mismatch error will occur. Syntax: LET <variable>= <value or expression> Practical Time CLS LET A= 20 LET B = 30 LET SUM = A+B PRINT “The Sum is”; SUM END CLS statement This command is used to clear the previous output screen. If you write CLS statement in the middle of the program, then you cannot see the outputs generated before execution of CLS because it clears the screen. Syntax: CLS REM statement REM statement is a non-executable statement and stands for remarks. It is a basic declaration statement that allows explanatory remarks to be inserted in a program. The remarks may be useful in a program to explain about different kinds of statements and user defined words. Syntax: REM <text for remarks> PRINT statement PRINT command is used to display any message or value on the screen. PRINT statement provides output on the screen. It prints the values of the expression on the screen. If
275 New Gateway to Computer Science Book-8 the expression list is blank, no characters are printed. The expressions in the list may be numeric or string. We can use semicolon and comma with a print statement which results differently than a normal PRINT statement. If expression list ends with comma or semicolon, the next PRINT statement prints on the same line. Comma provides a TAB space, but semicolon provides only one space. Syntax : PRINT [“Message”]; expression Practical Time A program to display the text or number on the screen. CLS PRINT “We are learning QBASIC programming.” PRINT PRINT “Learning QBASIC is fun.” PRINT 98511 PRINT “The number is:” ; 22004 END INPUT statement INPUT statement in QBASIC is used to accept the data item from the user. It allows entering values into the computer’s memory during the program execution. This statement will print and wait for the user to enter the value and then assign this value to a variable. Syntax : INPUT [“Message”]; Variables Practical Time A program to find out the sum of any three numbers. CLS INPUT “Enter the first number: ”; A INPUT “Enter the second number: ”; B INPUT “Enter the third number: ”; C SUM = A + B + C PRINT “The sum of the three number is : ”; SUM END Output We are learning QBASIC programming Learning QBASIC is fun 98511 The number is: 22004 Output Enter the first number: 20 Enter the second number: 30 Enter the third number: 40 The sum of the three number is :90
276 New Gateway to Computer Science Book-8 END statement END statement is used to terminate or quit from the QBASIC program. It can be used only one time in one program. Syntax: END Selection Structure It is also known as branching structure that allows you to transfer the program control from one part to another on the basis of specified condition or without condition. Here, we are going to learn some selection structures in QBASIC. IF......THEN Statement It helps the computer to check whether the relation is TRUE or FALSE. This statement is used to make the decision as well as comparison. Syntax IF <condition> THEN (statement) END IF Practical Time A program to check whether the entered number 10 is greater than 2 or not. CLS INPUT A , B IF A> B THEN PRINT A; "is greater than 2." END IF END Practical Time A program to check whether the entered number is divisible by 2 or not. CLS N = 10 IF N MOD 5 = 0 THEN PRINT “it is divisible by 2.” END Output 10 is greater than 2. Output it is divisible by 2.
277 New Gateway to Computer Science Book-8 IF......THEN……..ELSE Statement It is the two way decision making statement that can decide which part of statement it has executed when the condition is true or false. It executes one part of a program if the condition is true and another part if the condition is not true or false. Syntax: IF <condition> THEN (statement 1) ELSE (statement 2) END IF Practical Time A program to check whether the entered number is odd or even. CLS INPUT “Enter the number” ; N R = N MOD 2 IF R = 0 THEN PRINT “It is an even number” ELSE PRINT “It is odd number” END IF END Practical Time A program to check whether the number is divisible by 4 and 6 or not. CLS INPUT “Enter the number” ; N IF N MOD 4 = 0 and N MOD 6 = 0 THEN PRINT “The number is divisible by 4 and 6” ELSE PRINT “The number is not divisible by 4 and 6” END IF END
278 New Gateway to Computer Science Book-8 If.....Then....Else If......Else statement It is multi-way decision making statement that is used when there is two or more conditions to be evaluated. Syntax: IF <condition 1> THEN (statement 1) ELSE IF <condition 2> THEN (statement 2) …………………… …………………… ELSE (statement N) [N = any number] END IF A program to print the greatest number among three different numbers. CLS INPUT “Enter first number”; A INPUT “Enter second number”; B INPUT “Enter third number”; C IF A>B AND A>C THEN PRINT A; “is greater” ELSEIF B>A AND B>C THEN PRINT C; “is greater” ELSE PRINT C; “is greater” END IF END Practical Time
279 New Gateway to Computer Science Book-8 LET is an assignment statement which is used to assign the value to a variable. CLS command is used to clear the previous output screen. PRINT command is used to display any message or value on the screen. INPUT statement in QBASIC is used to accept the data item from the user. END statement is used to terminate or quit from the QBASIC program. Selection structure is also known as branching structure that allows you to transfer the program control from one part to another. IF......THEN statement helps the computer to check whether the relation is TRUE or FALSE. IF......THEN……..ELSE statement is the two way decision making statement that can decide which part of statement it has executed when the condition is true or false. If.....Then....Else If......Else statement is multi-way decision making statement that is used when there are two or more conditions to be evaluated. Quick Learn QBASIC looping Structure A looping structure is a logic which is used to execute one or more than one statements for a number of times. A loop allows a group of statements to be executed a certain number of times depending upon the condition. Here we are going to discuss some looping structures. For........Next Statement It repeats a block of statement for specified number of times. It is used to execute a series of instructions for a given number of times. Syntax: FOR <control variable> = <initial value> TO <ending value> STEP <N> (Statement block) NEXT < control variable>
280 New Gateway to Computer Science Book-8 A program to display the number from 1 to 50. CLS FOR I = 1 TO 50 PRINT I; NEXT I END Practical Time A program to display the number such as 1, 3 , 5 , 7 , 9 CLS FOR I = 1 TO10 STEP 2 PRINT I; NEXT I END Practical Time While.....Wend Statement It executes a block of statements repeatedly till the specific condition is true. When the value of the condition is false, the loop stops. Syntax: WHILE <condition> (statement) (Increase / decrease the value of control variable) WEND A program to display the number such as 1,4 ,7 , 10………….25. CLS A = 1 WHILE A<=25 PRINT A A = A + 3 WEND END Practical Time
281 New Gateway to Computer Science Book-8 Do....Loop Statement It repeats a part of program while a condition is true or until the condition becomes true. This statement repeats block of statements while the condition is true or until the condition becomes true. Syntax 1 DO WHILE <condition> (statement) LOOP Syntax 2 DO (statement block) LOOP WHILE <condition> A looping structure is a logic which is used to execute one or more than one statements for a number of times. For........Next statement repeats a block of statement for specified number of times. While.....Wend statement executes a block of statements repeatedly till the specific condition is true. Do....Loop statement repeats a part of program while a condition is true or until the condition becomes true. Quick Learn 1. Fill in the blanks with suitable words. a. A set of characters that are allowed to use in QBASIC is known as ……… b. ………….. is a symbolic name that is used to store data in the computer’s memory. c. The value of …………… is fixed which is used in the program. d. …………….. command is used to clear the previous output screen. e. ……… statement in QBASIC is used to accept the data item from the user. EXERCISE
282 New Gateway to Computer Science Book-8 f. Selection structure is also known …………….. that allows you to transfer the program control from one part to another. g. IF-THEN-ELSE statement is the two way …………… statement that can decide which part of statement it has executed when the condition is true or false. h. A ……………….. is a logic which is used to execute one or more than one statements for a number of times. i. …………statement repeats a block of statement for specified number of times. j. While-Wend statement executes a block of statements repeatedly till the specific condition is ……………….. 2. State whether the following statements are true or false. a. QBASIC is the most popular low level programming language. b. The elements of QBASIC programming are character set, variables, constants, etc. c. The QBASIC variable consists of alphabets, numbers and some special characters. d. Numeric and string are the two types of variables. e. String constant consists of a sequence of digits with or without decimal value. f. Numeric constant is a string value which is used in program. g. Logical Operators combine two or more relational expressions to evaluate a single value as True or False. h. CLS is an assignment statement which is used to assign the value to a variable. i. PRINT command is used to display any message or value on the screen. j. IF-THEN statement helps the computer to check whether the relation is TRUE or FALSE. 3. Write down the function to the following QBASIC statements. REM , INPUT, END , LET, IF…..THEN, FOR….NEXT, WHILE……WEND, DO….LOOP 4. Write very short answer of the following questions. a. What are the character set used by QBASIC? b. Write a suitable example for string variable. c. Name two arithmetic operators. d. What are the types of logical operators? e. Which statement is used to clear the output screen?
283 New Gateway to Computer Science Book-8 f. Name any one selection structure of QBASIC. g. Name the looping structure that you know. 5. Write short answer to the following questions. a. What is QBASIC? Write its features. b. What are the elements of QBASIC programming? c. Define variable and constant. d. What are the types of variables? Explain them in short. e. What is an operator? Name the types of operators. f. What are statements? List out the name of statements. g. What is a selection structure? Write some selection structure. h. What is a looping structure? Write some looping structure. 6. Write long answer to the following questions. a. Explain the types of operators with its truth table. b. Explain the types of operators with examples. 7. Write QBASIC program for the following. a. To find out the smallest number among the four different given numbers. b. To display the natural number from 1 to 100. c. To display the add numbers from 1 to 50. d. To print the factors of a given number. e. To calculate the cube root of a given number. • Perform the following activities in your computer lab and note down the output. a. To find out the smallest number among the four different given numbers. b. To display the natural number from 1 to 100. c. To display the add numbers from 1 to 50. d. To print the factors of a given number. e. To calculate the cube root of a given number. Lab Activities
284 New Gateway to Computer Science Book-8 A program to display the number such as 100, 90, 80, 70, 60………up to 10. CLS N = 100 DO PRINT N; N = N – 10 LOOP WHILE N> = 10 END Write a program to calculate the sum of the first ten natural numbers. CLS I = 1 SUM = 0 WHILE I <=10 SUM = SUM + I I = I + 1 WEND PRINT SUM END Practical Time-1 Write a QBASIC program to find out the average of any two numbers. CLS INPUT “Enter the first number”; A INPUT “Enter the second number”; B AVG = (A+B)/2 PRINT “The average value is”; AVG END Practical Time-2
285 New Gateway to Computer Science Book-8 Write a QBASIC program to find out the area of a circle. CLS INPUT “Enter the radius of a circle”; R A = 3.14*R*R PRINT “The area of a circle is”; A END Practical Time-3 Write a QBASIC program to convert the kilometre into meter. CLS INPUT “Enter the kilometre value ”; K M = K * 1000 PRINT “The distance in meter is::”; M END Practical Time-4 Write a QBASIC program to print the factors of a given number. CLS INPUT “Enter any number”; N FOR I = 1 TO N IF N MOD I = 0 THEN PRINT I NEXT I END Practical Time-5
286 New Gateway to Computer Science Book-8 Write a QBASIC program to print the greatest number among ten different numbers CLS INPUT “Enter the first number”; A FOR I = 2 TO 10 INPUT “Enter the next number”; B IF B>A THEN A = B NEXT PRINT A; ” is the greatest number” END Practical Time-6 Write a QBASIC program to calculate the cube root of a given number CLS INPUT “Enter any number”; N A = N ^ (1 / 3) PRINT “Cube root of “; N; ” is “; A END Practical Time-7 Write a QBASIC program to calculate the area of circle. CLS INPUT “ENTER THE RADIUS OF CIRCLE”; R A = 3.141*R^2 PRINT “AREA OF CIRCLE =”; A END Practical Time-8
287 New Gateway to Computer Science Book-8 Write a QBASIC program to generate number series. 3,6,9...up to 15 terms. CLS N=15 FOR I = 3 TO N STEP 3 NEXT I PRINT I END Practical Time-9 Write a QBASIC program to display the series 1,2,4,7,11upto 15th term. CLS A=1 FOR I=1 TO 15 PRINT A; A=A + I NEXT END Practical Time-10 Write a QBASIC program to enter any two numbers and display the smaller one. CLS INPUT “ENTER ANY TWO NUMBERS”; A, B IF A < B THEN PRINT A; “IS SMALLER” ELSE PRINT B; “IS SMALLER” END IF END Practical Time-11
288 New Gateway to Computer Science Book-8 Write a QBASIC program to enter any 10 numbers and display the greatest one. CLS INPUT “ENTER FIRST NUMBER”; N FOR I = 2 TO 10 INPUT “ENTER NEXT NUMBER”; G IF G > N THEN N = G NEXT I PRINT “THE GREATEST NUMBER IS” ; N ENDIF END Practical Time-12 Write a QBASIC program to display the sum of numbers from 1 to 100. CLS S= 0 FOR I = 1 TO 100 S = S + I NEXT I PRINT “The total sum is:” ; SUM END Practical Time-13 Write a QBASIC program to convert the temperature Celsius into Fahrenheit. CLS INPUT “Enter the temperature in Celsius”; C F = (9*C/5) + 32 PRINT “The temperature in Fahrenheit is:” ; F END Practical Time-14
289 New Gateway to Computer Science Book-8 Write a QBASIC program to display the odd numbers from 99 to 1. CLS FOR I = 99 TO 1 STEP -2 PRINT I NEXT I END Practical Time-15 Write a QBASIC program to display the series : 3 , 6, 9, 12, 15, 18, 21, 24, 27, 30. CLS FOR I = 3 TO 30 STEP 3 PRINT I NEXT I END Practical Time-16
290 New Gateway to Computer Science Book-8 S. N. Area Topics No. of questions Types of questions 1 Fundamental Knowledge & Skill Computer • Introduction of computer • Introduction of Hardware • Introduction of Software • Input and Output Devices • Storage Devices • Introduction of Word Processing • Introduction of Spread Sheet •Introduction of Presentation Package b/w Knowledge Base 1 Skill 1 Low Ability 1 High Ability 1 2 ICT, Ethics and Cyber Laws • Concept ICT technology • Computer Ethics and cyber law • Computer Virus, remedy and protection • Introduction data communication and Network • Introduction of Web design • Use of Website, Internet and E-mail 2 1 1 3 Number System • Decimal to Binary and Vice versa • Binary Calculation: Addition and Multiplication 1 1 4 Computer Graphics •Introduction of computer Graphics • Uses of computer graphics in various field 2 1 1 5 Concept of computer Programming • Basic Concept of Computer Programming 1 1 Total 10 3 3 2 2 Practical Part Full Marks:50 Time: 1: 00 Pass Marks: 20 SN Area Topics No of Question Marks 1 Fundamental Knowledge & Skill Computer • Creating document by following instructions. • Create four different types of data and show in chart • Insert given data according to instructions • To create four Power Point slides and presentation 1 25 2 Computer Graphics • Develop simple Web page using HTML Tags • Develop four colour Book Design 1 25 Specification Grid Computer Education Class 8 Theory Part Full Marks: 50 Pass Mark: 20 Time: 1:30 Hours
291 New Gateway to Computer Science Book-8 Class: 8 Full Marks: 50 Time: 1 Hour 30 minutes Pass Marks: 20 Group ‘A’ [10X1=10 Marks] Very Short Questions 1. Who is known as the father of computer? 2. What is the name of the first electro-mechanical computer? 3. Which network is called the network of networks? 4. What do you call for the first page of website? 5. In which number system does the digital computer work? 6. How many number are there in a binary number system? Write them. 7. Write down any two photo editing software. 8. What is a multimedia? 9. Write the full form of: i. W.W.W ii. G.U.I iii. U.N.I.V.A.C iv. Ms-word Group ‘B’ [7X4=28 Marks] Short Questions 1. What is an I.P.O. cycle? Describe with figure. 2. List out the components of MS-Excel. 3. Write down any five provisions of cyber ethics. 4. List out the devices required to connect the internet. 5. Write the features of a page layout. 6. Write short notes on: i. Photoshop ii. Adobe InDesign 7. (a) Convert decimal number into binary numbers. i. 75 ii. 100 (b) Binary Addition i. 1012 + 1112 ii. 1112 + 1002 Group ‘C’ [2X6=12 Marks] Long Questions 1. What is a flowchart? Draw the symbols used in flow chart and write its work. 2. What is an operating system? Write its types and describe in brief. MODEL QUESTION (Issued by CDC)
292 New Gateway to Computer Science Book-8 NOTE