#include <iostream> using namespace std; int main() { int num,count=0; cin>>num; for (int i=2;i<=num/2;i++)//事实上,若2~(num/2)范围内没有可以整除num的数,num便为质数 { if (num%i==0) {cout<<"不是质数"; count=1; break; } } if (count==0) cout<<"是质数"; // write your code here....