c++ - 不知道为什么我在使用 cin 和 getline 时遇到 C++ 错误

Question

我正在尝试浏览格式如下的 CSV 文件：

4305,2.7,59338,"Autauga County, AL"
14064,2.7,57588,"Baldwin County, AL"

这是代码的改编版本：

using namespace std;
 int main(){
    string newl;
    //getline(cin, newl);

 while(getline(cin,newl,',')){

    double cases1 = stod(newl);
    //cin.ignore();
    cout << cases1 << ' ';
    cout << "numbaone" << endl;

    getline(cin,newl,',');
    //cin.ignore();
    double unemploymentrate1 = stod(newl);
    cout << unemploymentrate1 << ' ';
    cout << "numbatwo" << endl;


    getline(cin,newl,',');
    double income1 = stod(newl);
    cout << income1 << ' ';
    cout << "numbathree"  << endl;

    cin.ignore();
    getline(cin,newl);
    }
 }

当我只输入一行时，它给了我正确的输出，对于 1882,3.1,46064,"Bibb County, AL" 是

1882 numbaone   
3.1 numbatwo    
46064 numbathree

但是，当我复制并粘贴多行作为输入时，例如

1530,3.8,34382,"Barbour County, AL"
1882,3.1,46064,"Bibb County, AL"

输出变得非常混乱：

1530,3.8,34382,"Barbour County, AL"
1882,31530 numbaone
3.8 numbatwo
34382 numbathree
.1,46064,"Bibb County, AL"
1882 numbaone
3.1 numbatwo
46064 numbathree

任何帮助将不胜感激。

Answer 1

您需要定义一个字符串流来解析每一行的数据。

#include <iostream>
#include <sstream>

using namespace std;

int main() {

    string newl;

    while (getline(cin, newl)) {

        stringstream stream(newl);

        getline(stream, newl, ',');
        double cases1 = stod(newl);
        cout << cases1 << ' ';
        cout << "numbaone" << endl;

        getline(stream, newl, ',');
        double unemploymentrate1 = stod(newl);
        cout << unemploymentrate1 << ' ';
        cout << "numbatwo" << endl;

        getline(stream, newl, ',');
        double income1 = stod(newl);
        cout << income1 << ' ';
        cout << "numbathree" << endl;
    }
    return 0;
}