Control Flow Statement in Python

Control Flow Statement in Python

A computer always executes a program sequentially. It starts execution from the first statement and ends at the last statement. This order of execution of statement(s) is called Flow of Control. But if you want some statements to print after fulfilling some condition then this can be achieved by using the control flow statement.

The control flow statement or control statements are used to control the flow of execution of the program. There are three different types of control flow statements in python:

• Sequential
• Decision making or selection
• Looping or iterative

Sequential – Sequential execution of statements is the default behaviour of the program, in which it executes one line after another.

Decision Making or Selection – Decision making statement is also called selection statement. Here, the execution of the statements depend upon the condition. Once the condition is fulfilled then the control of the flow will move accordingly. In python there are three types of selection statements:

• If
• If-else
• If-elif-else

Looping or iterative – used for repeating a set of statements multiple times in a row. In python there are two types of loops:

• While
• For

Simple program and its Flow chart 

Example 1	Example 2
print(“Hello World”) print(“I am”) print(“Python”) print(“Programming”)	a=10 b=20 c=a + b print(“Addition=“,c)

Simple Program Using Control Flow Statement

Program	Flow Chart
a = input(“Enter any text:: ”) if a = “bad morning”: print(“Sorry, I cannot print this text”) else: print(a)

IF ELSE STATEMENT

A ‘if’ statement is used to execute the specific block of code based on a condition. If the condition is ‘true’ then the True statement block will execute and if the statement is ‘false’ then the False statement block will execute.

Flow chart to check odd or even number

Simple program to check odd or even number

num = int(input(“Enter a number: “))

a = num%2

If a == 0:

 print(“The number is Even”)

else:

 print(“The number is Odd”)

Output –

Enter a number: 5

The number is Odd

Enter a number: 4

The number is Even

IF ELIF ELSE STATEMENT

A ‘if’ statement is used to execute the specific block of code based on a condition, if that ‘if’ condition does not give the True result then it moves on to ‘else if’ or elif statement and it continues to do this until it reaches the else statement.

Check the greatest number among three number

print("Enter any three numbers: ")

a=int(input())

b=int(input())

c=int(input())

if a>b and a>c:

 print("First no is greatest")

elif b>c and b>a:

 print("Second no is greatest")

else:

 print("Third no is greatest")

Output –

Enter any three numbers:

34

45

33

Second no is greatest