A positive integer number greater than 1 which has no other factors other than 1 and itself is called a prime number. 2, 3, 5, 7, 11, 13 etc. are prime numbers as they do not have any other factors other than 1 and itself.
For Prime Number Algorithm and Pseudocode, you can refer our previous post Algorithm or Pseudocode to find whether a Number is Prime Number or Not
Problem Statement for Below Program
Write a program to check whether a given number is Prime or not in Python
Source Code
##To find whether a number is prime or not
## Prime Number is a number which is divisible only by 1 and itself.
def prime(n):
if n in (0,1):
return "Number is not a prime number"
## A counter to check if the number is divisible or not inside the for loop
counter=0
## Start the loop from 2 to n-1. In range the loop is executed till n-1. Also we have given the start range.
for each in range(2, n):
if n % each == 0: ## checks if the number is divisible by any other number in this loop.
counter += 1 ## If yes counter is incremented.
## If the counter is incremented that means the number is divisible inside the loop. If the counter is zero means it is a Prime Number.
if counter == 0:
return "Number is a Prime Number"
else:
return "Number is not a prime Number"
if __name__ == '__main__':
num = int(raw_input("Enter a number"))
result = prime(num)
print result
Output
Enter a number 5
Number is a Prime Number