判断质数和合数

#include <iostream>
using namespace std;
int main(int argc, char** argv) {
    int c;
    cout<<"请输入你要判断的数:"<<endl;
    system("pause");
    cin>>c;
    if(c%2==0||c%3==0){
    cout<<"这个数是合数";        
        }else if(c%1==0&&c%c==0){
       cout<<"这个数是质数";
       }else if(c==1||c==2||c==3){
           cout<<"这个数是质数";
       }
    return 0;
    
}