每行第一个输入为c，表示后面c个整数相加求平均数输出精度为小数点后两位可多行输入直到c输入为0#include <iostream>using namespace std;#include<iomanip>int main(){ int a, c; double sum,sum2; while (cin >> c && c) { sum = 0; for (int i = 0; i < c; i++) { cin >> a; sum += a; } sum2 = sum*1.0 / c; cout <<fixed<< setprecision(2) << sum2<< endl; }}