c++ - 将 cin 数据提取到适合的变量

Question

如果输入无效，我想从 cin 中提取无效输入并将其存储在适合的变量中。我怎样才能做到这一点？

#include<iostream>

using namespace std;

int main(){
    int number;
    cout << "Enter a number: " << endl;
    cin >> number;

    if(cin.fail()){
    cout << "Error!" << endl;
    //HOW CAN I STORE THE INVALID INPUT WHICH IS STORED IN cin INTO A STRING?
    }   

return 0;

Answer 1

当您检测到 failbit 已设置时，将其重置，并使用 std::getline 将整行无效输入读入 std::string 来自 std::cin:

#include <iostream>
#include <string>


int main()
{
        int number;

        while(true)
        {
                std::cout << "Enter a number (0 to exit): " << std::endl;
                std::cin >> number;

                if(std::cin.fail())
                {
                        std::string error_data;
                        std::cin.clear(std::cin.rdstate() & ~std::ios::failbit);
                        std::getline(std::cin, error_data);
                        std::cout << "You didn't enter a number - you've entered: " << error_data << std::endl;

                }
                else
                {
                        std::cout << "Number is: " << number << std::endl;
                        if(number == 0)
                        {
                                break;
                        }
                }

        }
        return 0;
}