int isPrime(int n) { if (n < 2) return 0; for (int i = 2; i <= n / 2; i++) if (n % i == 0) return 0; return 1; }#include <stdio.h> main() { int n, i, c = 0; printf("Enter any number n:"); scanf("%d", &n); //logic for (i = 1; i <= n; i++) { if (n % i == 0) { c++; } } if (c == 2) { printf("n is a Prime number"); } else { printf("n is not a Prime number"); } return 0; } Program Output:#include <stdio.h> main() { int n, i, c = 0; printf("Enter any number n:"); scanf("%d", &n); //logic for (i = 1; i <= n; i++) { if (n % i == 0) { c++; } } if (c == 2) { printf("n is a Prime number"); } else { printf("n is not a Prime number"); } return 0; } Program Output:#include<stdio.h> void main() { int num; int prime = 1; printf("Enter a number = "); scanf("%d",&num); for(int i = 2; i < num; i++) { if(num % i == 0) { prime = 0; break; } } if(prime == 1 && num>0 && num !=1) printf("%d is a prime number.", num); else printf("%d isn't a prime number.", num); } #include<stdio.h> void main(){ int num, i; int cp = 1; printf("Enter a number = "); scanf("%d",&num); if(num > 0){ for(i = 2; i < num; i++){ if(num % i == 0){ cp = 0; } } if(cp == 1){ printf("%d is a prime number.", num); } else{ printf("%d isn't a prime number.", num); } } }#include <stdio.h> // Mahmudur Rahman Mahin int main() { int i, n, flag = 1; scanf("%d", &n); if (n<=1) { flag = 0; } else{ for (i = 2; i < n; i++) { if (n % i == 0) { flag = 0; break; } else { flag = 1; } } } if (flag == 1) { printf("Prime number"); } else { printf("Not Prime Number"); } return 0; }#include <stdio.h> #include <stdlib.h> int main(void) { int n,i,f=0; setbuf(stdout,NULL); printf("Enter the number to check whether it is a Prime Number or not = "); scanf("%d",&n); for(i=2;i<=(n/2);i++) { if(n%i==0) { f=1; break; } } if(f==1) printf("It is not a Prime Number"); else printf("It is a Prime Number"); return EXIT_SUCCESS; }#include<stdio.h> int main(){ int n,i,m=0,flag=0; printf("Enter the number to check prime:"); scanf("%d",&n); m=n/2; for(i=2;i<=m;i++) { if(n%i==0) { printf("Number is not prime"); flag=1; break; } } if(flag==0) printf("Number is prime"); return 0; } flag=0; scanf("%d", &num); for(i=2;i<=(num/2);i++) { if(num%i==0) flag=1; } if(flag==0) printf("%d is a prime number",num);