#include<iostream>
using namespace std;
int main(int argc, char *argv[]){
double sum=0;
float monthConsume;
for(int i=0;i<12;i++){
cin>>monthConsume;
sum+=monthConsume;
}
cout<<"$"<<sum/12<<endl;
return 0;
}
原文：http://www.cnblogs.com/lcchuguo/p/5303138.html