程式設計範例(質數測試1)

#include
using namespace std;
void main(){
cout<<"Please input a number:";int n;cin>>n;
int sum=0;
for(int i=0;i<=n;i++) sum+=i*i;
cout--endl<<"1^2+2^2+...n^2="--sum;
cout--endl<<"n(n+1)(2n+1)/6="--n*(n+1)*(2*n+1)/6;
}