做 while 循环..现在：无限，目标：不是无限（问直到循环）

Question

所以当我输入一个字符或字符串时，它会无限次地再次询问这个问题......但我希望它每次都问一次错误，如果错误再问一次。得到它... ？ :( 现在循环是无限的。

#include <iostream>
using namespace std;

int main() {
float money;

do
{
cout << "How much money do you have? " << endl;
cin >> money;

    if (money) {
       cout << "You have: " << money << "$" << endl;
    } else {
       cout << "You have to enter numbers, try again." << endl;
    }
} while (!money);

return 0;
}

Answer 1

您没有验证和清除 cin 流的错误状态。试试这个：

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

int main() {
    float money;

    do
    {
        cout << "How much money do you have? " << endl;

        if (cin >> money) {
            // a valid float value was entered

            // TODO: validate the value further, if needed...

            break;
        }
        else {
            // an invalid float was entered

            cout << "You have to enter numbers, try again." << endl;

            // clear the error flag and discard the bad input...
            cin.clear();
            cin.ignore(numeric_limits<streamsize>::max(), '\n');
        }
    }
    while (true);

    cout << "You have: " << money << "$" << endl;

    return 0;
}

做 while 循环..现在：无限，目标：不是无限（问直到循环）

Do while loop.. right now: infinite, goal: not infinite (ask until loop)

c++

windows

loops

while-loop

do-while