#include<bits/stdc++.h>using namespace std;int main(){ int year; cin>>year; if((year%4==0 and year%100!=0) or year%400==0) { cout<<"闰年"; } else{ cout<<"不是"; }}
#include<iostream>#include<cmath>using namespace std;int main(){ double a,b,c; cin>>a>>b>>c; double m=(a+b+c)/2.0; double s=sqrt(m*(m-a)*(m-b)*(m-c)); cout<<s;}
水个帖子。