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对于以下内容，我试图将用户输入限制为仅 Y 或 y 或 N 或 n。请遵循我对代码的评论，以便我指出问题所在。我是这个论坛的新手，我对编程充满热情，如果有人可以请帮助我。谢谢你。while 循环（不是 do-while 循环）是我遇到问题的部分。我想也许我没有正确使用 != 。我还没有什么太高级的东西，我现在的班级只是入门级。 

    cout << "Would you like to use this program again?: ",
    cin >> ans;

    if(ans =='Y'||ans =='y'||ans =='N'||ans =='n')
        break;
    else //This is where I'm having problem with.
        while (ans != 'Y'||ans != 'y'||ans !='N'||ans !='n')
        {
            cout << "Please enter Y or y if you like to use the program again and N or n do exit.",
            cin >> ans; //If the question is asked and no matter what I input for ans, the while loop never gets exited. Why? Is there something I didn't use right?
        }
}while (ans == 'Y'||ans =='y');

return 0;
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1 回答 1

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处理逻辑的更好方法是有一个do循环，不断提示用户输入是/否，直到他给出它：

do {
    cout << "Please enter Y or y if you like to use the program again and N or n do exit.",
    cin >> ans;
} while (ans != 'Y' || ans != 'y' || ans !='N' || ans !='n');
于 2016-04-01T11:04:34.003 回答