prime or not in c code example

Example 1: prime chec kin c

int isPrime(long long number) {

	if (number == 0 || number == 1 || (number % 2 == 0 && number > 2)) {
		return 0;
	}

	else {
		for (long long i=3; i <= (long long)sqrt(number)+1; i++) {
			if (number % i == 0) {
				return 0;
			}
		}
		return 1;
	}
}

Example 2: prime numbers in c

#include<stdio.h>
main() {
    int n, i, count=0;
    printf("Enter Number");
    scanf("%d",&n);
   
    for ( i = 1; i<= n; i++) {
        if (n % i == 1) {
            count++;
        }
    }
    if( count == 2) {
        printf("Prime Number");
    }
    else {
        printf("Not A  Prime Number");
    }
}

Example 3: prime number c

#include <stdio.h>
int main()
{
   int i, num, p = 0;
   printf("Please enter a number: \n");
   scanf("%d", &num);
   for(i=1; i<=num; i++)
   {
      if(num%i==0)
      {
         p++;
      }
   }
   if(p==2)
   {
      printf("Entered number is %d "\
             "and it is a prime number.",num);
   }
   else
   {
      printf("Entered number is %d "\
             "and it is not a prime number.",num);
   }
}