itsa [C_AR021-易]成績統計

1.需要再四捨五入到第一位
(floor( X * 10 + 0.5)) / 10;  //10需根據小數幾位而變化

#include<iostream>
#include<cmath>
#include<iomanip>
using namespace std;

int main()
{
int n;
double chinese, english, math, allavg = 0, cavg = 0, eavg = 0, mavg = 0;
cin >> n;
for (int i = 0; i < n; i++)
{
cin >> chinese >> english >> math;
allavg += chinese + english + math;
cavg += chinese;
eavg += english;
mavg += math;
}
allavg = (floor((allavg / (3 * n)) * 10 + 0.5)) / 10;
cavg = (floor((cavg / n) * 10 + 0.5)) / 10;
eavg = (floor((eavg / n) * 10 + 0.5)) / 10;
mavg = (floor((mavg / n) * 10 + 0.5)) / 10;
cout << fixed << setprecision(1) << allavg << " " << cavg << " " << eavg << " " << mavg << endl;
return 0;
}