当cin的输入是“点"时，while循环到无穷大 [英] while loop to infinity when the input of a cin is a 'dot'

问题描述

使用cin方法获取变量时遇到麻烦.当输入是数字时，没有问题，但是当它是特殊字符(例如点[.])时， whileloop循环成无穷大. 我在做什么错了?

I am having trouble using the cin method to acquire a variable. When the input is a number there is no problem, but when it is a special character like a dot [.], the whileloop loops into infinity. What am I doing wrong?

cout << "What is your race" <<endl<<"1.Human\n2.troll\n3.zombie"<<endl;
    cin >> *race;
    while(*race<1||*race>3)
    {
    system("cls");
    cout << "Wrong choice"<<endl<< "What is your race" <<endl<<"1.Human\n2.troll\n3.zombie"<<endl;
    cin >> *race;
    }

我搜索了答案，我应该刷新缓冲区，但是我不知道该怎么做.我对c ++还是很陌生.谢谢

I searched for the answer and i should have to flush the buffer but i don"t get how to do it. I'm rather new with c++. Thanx

推荐答案

将race设置为字符，则您可以执行以下操作:

Make race an char, then you will be able do to:

while (*race < '1' || *race > '3')

这可能是您想要实现的.

which is probably what you want to achieve.

说明:

当您将cin >>转换为int时，它将给定的ASCII字符串转换为整数值. .没有整数含义，因此不会将其读入race且已设置failbit-进一步>> s禁止操作，直到您将其清除.但是，如果您cin >>进入char并将其与其他char(实际上是它们的ASCII码)进行比较，则可以毫无问题地进行检查.

When you cin >> into an int, it converts given ASCII string to integer value. . doesn't have an integer meaning, so it isn't read into race and failbit is set - further >>s are no-op, until you clear them. However, if you cin >> into char and compare it with other chars (well, their ASCII codes, actually), you will be able to check it without troubles.

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