如何在c ++中捕获无效的输入？ [英] How to catch invalid input in c++?

问题描述

我是一个（有点）经验丰富的python程序员试图迁移到C ++。我想要能够捕获无效的用户输入。例如，如果一个变量需要一个整数，并且用户键入一个字符串，我想捕获该错误。在python 3中，语法是：

I am a (somewhat) experienced python programmer trying to migrate to C++. I want to be able to catch invalid user input. For instance, if a variable requires an integer, and the user types a string, I want to catch that error. In python 3, the syntax is:

try:
    #block of code you want to run
except ValueError:
    #Block of code to be run if the user inputs an invalid input

在c ++我读到的语法是Try，catch。我试图这样做，但它不工作。这里是我的代码在c ++：

In c++ I read that the syntax is Try, catch. I am trying to do that, but its not working. here is my code in c++:

#include "Calculator.h"
#include <iostream>
#include <exception>

using namespace std;

Calculator::Calculator()
{
}

int Calculator::Calc()
{
    cout << "Enter a number " << endl;
try
{
    cin >> a;
}
catch (logic_error)
{
    cout << "An error has ocurred! You have entered an invalid input!"
}

如何在c ++中捕获无效的输入？是的，我使用一个头文件为这个类。如果你需要这些内容，让我知道。

How can I catch invalid input in c++? Yes, I am using a header file for this class. If you need those contents, let me know. I will continue to search the web and post if I have found an answer!

推荐答案

您将需要 #include< limits>

int x;
std::cout << "Enter a number: ";
std::cin >> x;
while(std::cin.fail()) {
    std::cin.clear();
    std::cin.ignore(numeric_limits<streamsize>::max(),'\n');
    std::cout << "Bad entry.  Enter a NUMBER: ";
    std::cin >> x;
}
std::cout << "x = " << x << std::endl;

有一个模板。

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