By Ralph
Friday November 6, 2009
#include <iostream>
#include <vector>
#include <cmath>
using namespace std;
// Tests whether a function is prime
bool test_prime(int num){
int count = 0,x=2;
double numx = (double) num;
// Go through all primes
for(x=0;x<sqrt(numx);x++){
if(num % x == 0){
return false;
}
}
return true;
}
int main(int argc, char *argv[]){
int num;
if(argc != 2){
cerr << "Usage: " << argv[0] << " positive-integer" << endl;
return -1;
}else{
num = atoi(argv[1]);
}
bool is_prime = test_prime(num);
if(is_prime){
cout << num << " is prime" << endl;
}else{
cout << num << " isn't prime" << endl;
}
}
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