Question

Write a program in python to test if given number is prime or not.

Answer 1

num = int(input("Enter a number to test if it's prime or not: "))

if num%2 == 0:

   if num == 2:

       print(num,"is prime")

   else:

       print(num,"is not prime")

else:

   count = 0

   for x in range(2,num):

       if num % x == 0:

           count+=1

   if count==0:

       print(num,"is prime")

   else:

       print(num,"is not prime")

I wrote my code in python 3.8. I hope this helps!

Answer 2

Answer:

Answer:

def main():

num = int(input("Input a number to check for prime: "))

if num > 1:

 for i in range(2,num):

  if (num % i) == 0:

   print("%d is not a prime number" % num)

   break

  else:

   print("%d is a prime number" % num)

   break

else:

 print("%d is not a prime number" % num)

 

if __name__ == "__main__":

main()

Explanation:

Solution retrieved from programiz.com.

Note, this program uses the idea of the Sieve of Eratosthenes to validate the input number by using the modulo operator to determine primeness.

The program will output to the user if the number input is indeed prime or not.

Cheers.

Explanation: