有人可以告诉我为什么我的分数总是计算为零？

Question

有人能告诉我为什么变量百分比= 0？它应该是33.3333对吗？(2/6)

因为当我运行下面的函数时,结果是

总行数= 6
奇数行= 2
奇数行百分比= 0

bool count_odd_lines(string a, string b)
{
    ifstream in;
    ofstream out;
    in.open(a.c_str());
    out.open(b.c_str()); 
    string s;
    int count = 0;
    int odd =  0;  
    if (in && out)
    {
        while (getline(in, s))
        {
            count++;
            if (s.length() % 2 != 0) odd++;
        }
        out << "Total lines = " << count << endl;
        out << "Odd lines = " << odd << endl;
        double percent = odd/count;
        out << "Percent odd lines = " << setprecision(4) << percent <<endl;
        return true;
    }
    else return false; 
    in.close();
    out.close();
}

Answer 1

问题是你正在进行整数除法.更改:

double percent = odd/count;

至

double percent = static_cast<double>(odd)/count;

Answer 2

有两个问题:

1. 两个odd和count是整数,所以odd/count执行整数(即,截断)分裂.
2. 要获得百分比(即33.33而不是0.3333),您需要将结果乘以100.

您可以解决这两个问题:

double percent = odd * 100.0 / count;

乘法进行缩放,并将后续除法转换为浮点除法.