c++ - 在预测错误的用户输入的情况下获取数字的平均值

Question

#include <iostream>
#include <string>

using namespace std;

int main(void) {

    float sum, counter = 0, num;
    string d;
    bool t = true;

    while (t) {
        cin >> num;
        sum = sum + num;

        counter += 1;

        while (cin.fail())
        {
            cin.clear();
            cin.ignore();
            cin >> d;

            if (d == "done") {
                t = false;
                continue;
            } else {
                cout << "Invalid" << endl;
                continue;
            }
        }
    }
    cout << sum << ' ' << counter << ' ' << (sum / counter);
    return 0;
}
     

**因此，我尝试使用输入猜测来计算输入数字的平均值，如下所示:

4 5 BadInput 7
-----
Expected output should be:
Enter a number: 4
Enter a number: 5
Enter a number: bad data
Invalid 
Enter a number: 7
Enter a number: done
16 3 5.333333333333333

我的代码有什么问题？

Answer 1

如果要处理错误的输入，建议将输入读入字符串，然后进一步处理该字符串。这将使循环本身更加简单:

std::string d;
float sum = 0;
int counter = 0;

while (std::cin >> d) {
    if (d == "done") {
        break;
    }

    try {
        sum += std::stof(d);
        counter++;
    } except (std::logic_error &e) {
        std::cerr << "Invalid input\n";
    }
}

std::cout << sum << ' ' << counter << ' ' << (sum / counter) << '\n';