需要有cout / cin的有效输入 [英] Requiring valid input with cout/cin

问题描述

我有一个游戏，用户需要在一定范围内输入x和y坐标，一次一个。现在我的输入代码如下：

I have a game where the user needs to enter x and y coordinates within a certain range, one at a time. Right now my input code is as follows:

do {
    printf("\n");
    cout << "X: ";
    cin >> x;
    cout << "Y: ";
    cin >> y;
} while (cin.fail());

我刚接触c ++，但是阅读文档使我相信这是一个可以接受的验证用户输入。它在输入有效时工作得很好，但是当输入是不同类型（例如输入a）时，它用X：Y：无限循环。

I'm new to c++ but reading documentation lead me to believe this was an acceptable method for verifying user input. It works perfectly when the input is valid, however when the input is of a different type (for instance entering "a") it infinitely loops with "X: Y: ". What do I need to do differently to have it wait for user input as if the lines were being read for the first time?

推荐答案

考虑如果我跳过无效的输入并输入： 3e4 40。我的意思是34 40，但是跳过e可能会使3 4，并留下40用于以后或可能离开4 40。

Consider if I skip invalid input and enter: "3e4 40". I meant "34 40", but skipping the e might make "3 4" and leave "40" for later or might leave "4 40".

a href =http://en.cppreference.com/w/cpp/string/basic_string/getline =nofollow> getline 读取整行并解析它，例如使用 istringstream 就像你现在 - 任何错误变成一个错误，而不离开输入流在一个奇怪的状态。

Consider using getline to read a whole line in and parsing it such as with istringstream just as you are now -- any error becomes an error without leaving the inputstream in a weird state.

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