#geshi(cpp){{
#include <iostream>
#include <cmath>
#include <sstream>
using namespace std; int main( int argc, char** argv ){
int x; bool is_prime = true;
if(argc < 2){
cout << "Input x > ";
cin >> x;
}else{
istringstream is(argv[1]);
is >> x;
}
for( int i = 2; i < static_cast<int>(sqrt(x)) + 1; i++){
if(( x % i ) == 0 ){
is_prime = false;
break;
}
}
if( is_prime ) cout << x << "は素数" << endl; else cout << x << "は非素数" << endl; return 0;
} }}