Alright have finally done it. And this is my code. See if there is anything that could be truncated or left off. I appreciate it. And thanks Cornedbee for clarifying the question.

Code:#include <iostream> #include <math.h> using namespace std; // Function must be declared before being used. int prime(int n); int main(){ int i; // Set up an infinite loop; break if user enters 0. // Otherwise, evaluate n from prime-ness. while(1){ cout << "Enter a number (0 to exit)"; cout << "and press ENTER: "; cin >> i; if(i == 0) break; for(i = 2; i <= 22; i++) // Test all numbers from 2 to 22 if(prime(i)){ // state for each mumber whether it is a prime cout<< i << "is prime" << endl; // and print out all numbers. }else{ cout<< i << "is not a prime" << endl; } } return 0; } // Prime number function. Test divisors from // 2 to sqrt of n. Return false if a divisor // found; otherwise, return true. int prime(int n){ int i; for(i = 2; i <= sqrt((double) n); i++) if(n % i == 0) return false; // n is not prime. return true; // If no divisor found, n is prime. }