文件体验之读取、处理数据

#include <iostream>
#include <fstream>
using namespace std;

int main()
{
    int a=0,b=0,c=0,d=0,e=0;
    int s,i,r;
    double sum=0,ave;
    ifstream infile("english.dat",ios::in);
    if(!infile)
    {
        cerr<<" open error"<<endl;
        exit(1);
    }
    for(i=0;i<10000;i++)
    {
        infile>>s;
        sum+=s;
        r=s/10;
        switch(r)
        {
            case 10:
            case 9: a++;break;
            case 8: b++;break;
            case 7: c++;break;
            case 6: d++;break;
            default: e++;
        }
    }
    infile.close();
    ave=sum/10000;
    cout<<"优秀人数："<<a<<endl;
    cout<<"良好人数："<<b<<endl;
    cout<<"中等人数："<<c<<endl;
    cout<<"及格人数："<<d<<endl;
    cout<<"不及格数："<<e<<endl;
    cout<<"平均成绩："<<ave<<endl;
    return 0;
}