c++ getline没有得到输入

Question

我正在尝试输入一行，然后输入一个整数，然后再输入一行，但是当最后一个 cin 获取该行时，我按下回车键，它崩溃或随机输出到无穷大。怎么了？

int main(){
    string a= "", b = "";
    int n1 = 0, n2 = 0;

    getline(cin, a);
    cin >> n1;

    //when i input the next like it outputs randomly without continuing with the next like why?
    getline(cin, b);

    //it doesn't let me to input here coz it's outputting some random strings.
    cin >> n2;
    return 0;
}

感谢您的帮助，谢谢。

Answer 1

需要消耗换行符。

int main(){
    string a, b;
    int n1, n2;

    getline(cin, a);

    cin >> n1;
    cin.get(); // this will consume the newline
    getline(cin, b);

    cin >> n2;
    cin.get(); // this will consume the newline
}

std::getline 将为您使用换行符。

下面是示例用法:

21:42 $ cat test.cc 
#include <iostream>
#include <string>

using namespace std;

int main(){
    string a, b;
    int n1, n2;

    getline(cin, a);

    cin >> n1;
    cin.get(); // this will consume the newline
    getline(cin, b);

    cin >> n2;
    cin.get(); // this will consume the newline

    std::cout << a << " " << b << " " << n1 << n2 << std::endl;
}
✔ ~ 
21:42 $ g++ test.cc
✔ ~ 
21:42 $ ./a.out 
hello
4
world
2
hello world 42