检查输入值是一个整数 [英] Checking input value is an integer

问题描述

我输入这个，它要求用户输入两个整数，然后将变成变量。从那里将进行简单的操作。

I was typing this and it asks the user to input two integers which will then become variables. From there it will carry out simple operations.

如何让计算机检查输入的内容是否为整数？如果没有，请让用户输入一个整数。例如：如果有人输入a而不是2，那么它会告诉他们重新输入一个数字。

How do I get the computer to check if what is entered is an integer or not? And if not, ask the user to type an integer in. For example: if someone inputs "a" instead of 2, then it will tell them to reenter a number.

感谢

 #include <iostream>
using namespace std;

int main ()
{

    int firstvariable;
    int secondvariable;
    float float1;
    float float2;

    cout << "Please enter two integers and then press Enter:" << endl;
    cin >> firstvariable;
    cin >> secondvariable;

    cout << "Time for some simple mathematical operations:\n" << endl;

    cout << "The sum:\n " << firstvariable << "+" << secondvariable 
        <<"="<< firstvariable + secondvariable << "\n " << endl;

}

推荐答案

检查如下：

int x;
cin >> x;

if (cin.fail()) {
    //Not an int.
}

此外，您可以继续获取输入，直到获得int： / p>

Furthermore, you can continue to get input until you get an int via:

#include <iostream>



int main() {

    int x;
    std::cin >> x;
    while(std::cin.fail()) {
        std::cout << "Error" << std::endl;
        std::cin.clear();
        std::cin.ignore(256,'\n');
        std::cin >> x;
    }
    std::cout << x << std::endl;

    return 0;
}

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