i have to determine the number entered by the user is a prime number or not. plz if you can tell me than reply.
A prime number is 1 that has no integer divisors other than 1 and itself.
Once they have entered the number all you have to do is test that number to see if has any integer divisors other than 1 and itself.
Start a loop with an initial value of 2 and an initial maximum of the number.
Check to see if the number is exactly divisible by the loop control using % operator (number % control == 0), if it is the number is not prime
If the number is not prime then set your maximum to number / control. This will reduce the number of values you have to check.
If the loop ends without detecting the the number is not prime then the number is prime.