Design a function to check the given number is prime or not if prime return 1 else 0 in c

Design a Prime Number Checker Function in C

To design a function to check if a given number is prime or not and return 1 if prime else 0 in C, we can use the following algorithm:

1. Take the number as input.
2. Initialize a variable flag to 0.
3. Iterate from 2 to the square root of the number.
4. If the number is divisible by any of the numbers in the loop, set flag to 1 and break the loop.
5. If the loop completes without setting flag to 1, then the number is prime.
6. Return flag.

C code implements this algorithm:

int is_prime(int n) {
  int flag = 0;
  for (int i = 2; i <= sqrt(n); i++) {
    if (n % i == 0) {
      flag = 1;
      break;
    }
  }
  return flag;
}

This function can be used as follows:

int main() {
  int n;
  printf("Enter a number: ");
  scanf("%d", &n);

  int is_prime = is_prime(n);

  if (is_prime) {
    printf("%d is a prime number.\n", n);
  } else {
    printf("%d is not a prime number.\n", n);
  }

  return 0;
}

Example output:

Enter a number: 11
11 is a prime number.