2.1 Design a Solution

c) Explain each control structure and their

respective purposes.

d) Apply appropriate control structure.

Control Structure

• Sequence

• Selection

• Looping

What is a control structure?

1. Control structures control the flow of a program’s logic.

2. Consist of three structures:

i. Sequence structure

ii. Selection structure

iii. Looping structure

What is a control structure?

• Sequence Control Structure

• Performs actions one after another in sequence

• Selection Control Structure

• Performs action(s) based on a certain condition

• Repetition Control Structure

• performs one or more actions repeatedly while a certain

condition is true.

SEQUENCE STRUCTURE

• A sequence control structure performs actions one

after another in sequence

• All actions will be executed, none will be skipped

• Actions can be input, process, or output.

Example of Problem 1

•Find the sum and average of three

numbers input by user.

•Problem Analysis

•Input : num1, num2, num3

•Process : Calculate sum and average of

three numbers

•Output : sum, average

Example of Problem 1

Pseudocode

start

READ num1, num2, num3

sum = num1+num2+num3

average(num1+num2+num3)/3

PRINT sum, average

end

Example of Problem 1

• Flowchart start

READ num1, num2, num3

sum = num1+num2+num3

average = (num1+num2+num3)/3

PRINT sum, average

end

Example of Problem 2

Calculate and display the addition,

subtraction, multiplication and

division of two numbers.

Example Problem 2

• Write an IPO analysis for a program that

calculate and display the addition,

subtraction, multiplication and division of two

numbers.

Input number1, number2

Process

Output Calculate the addition, subtraction,

multiplication and division of two

numbers.

addition, subtraction, multiplication

and division

Example of Problem 2

Pseudocode

START

READ number1, number2

addition = number1 + number2

subtraction = number1 – number2

multiplication = number1 x number2

division = number1 / number2

PRINT addition, subtraction, multiplication,

division

STOP

Example of Problem 2

Flowchart START

READ number1, number2

addition = number1 + number2

subtraction = number1 – number 2

multiplication = number1 * number2

division = number1 / number2

PRINT addition, subtraction,

multiplication, division

STOP

Example of Problem 3

Calculate the total and average

of five subjects.

Example Problem 3

• Write an IPO analysis for a program that

calculate the total and average of five Marks.

Input mark1, mark2, mark3, mark4,

Process mark5

Output

Calculate the total and average

of five marks.

Total,average

Example of Problem 3

Pseudocode

START

READ mark1, mark2, mark3, mark4,

mark5

total = mark1 + mark2 + mark3 +

mark4 + mark5

average = total / 5

PRINT total , average

STOP

Example of Problem 3

Flowchart START

READ mark1,mark2, mark3,

mark4, mark5

total = mark1+mark2+mark3+mark4+mark5

average = total / 5

PRINT total , average

STOP

Example of Problem 4

Calculate the diameter,

circumference and area of a

circle.

Example Problem 4

• Write an IPO analysis for a program that

calculate the diameter, circumference and

area of a circle.

Input radius

Process

Output Calculate the diameter,

circumference and area of a

circle.

diameter, circumference and

area

Example of Problem 4

Pseudocode

START

READ radius

diameter = 2 x radius

circumference = 2 x 3.142 x radius

area = 3.142 x radius x radius

PRINT diameter, circumference, area

STOP

Example of Problem 4

Flowchart START

READ radius

diameter = 2 * radius

circumference = 2 * 3.142 * radius

area = 3.142 * radius * radius

PRINT diameter, circumference,

area

STOP

Example of Problem 5

Calculate the quotient and

remainder of a division.

Example Problem 5

• Write an IPO analysis for a program that

calculate the quotient and remainder of a

division.

Input number1, number2

Process

Output Calculate the quotient and

remainder of a division.

quotient, remainder

Example of Problem 5

Pseudocode

START

READ number1, number2

quotient = number1 / number2

remainder = number1 % number2

PRINT quotient, remainder

STOP

Example of Problem 5

Flowchart START

READ number1, number2

quotient = number1 / number2

remainder = number1 % number2

PRINT quotient, remainder

STOP

Example of Problem 6

• Calculate the discount and sale price of a book

after given 15% discount.

• Problem Analysis

• Input : original price

• Process : Calculate discount and sale price of

books

• Output : discount, sale price

• Pseudocode

start

Input original price

discount = 0.15 x original price

sale price = original price – discount

Output discount, sale price

end

• Flowchart start

Input original price

discount = 15% x original price

sale price = original price - discount

Print discount, sale price

end

Write a pseudocode & flowchart

1. Calculate the volume of cuboid.

2. Calculate the product of three numbers.

3. Calculate an average mark of 3 students.

4. Calculate a price of smartphone if 20% discount

is given to customer.

5. Calculate total and average of two numbers.