使用 ifstream 从文本文件中读取

Question

所以我正在尝试从文本文件中读取。它表明我可以成功地从文件中读取但是当我尝试计算这些值时，它只显示 0，而我在文本文件中有其他值。

#include <iostream>
#include <fstream>
#include <string>


using namespace std;

int main()
{

    std::ifstream file("numbers.txt");
if (file) {
    cout << "Managed to read file successfully. \n";
}else{
    cout << "Unable to read file.";
}


int x, y;

file >> x >> y;

cout << "Num 1: " << x << endl;
cout << "Num 2: " << y << endl;

    return 0;
}

Answer 1

带有 numbers.txt 文件

45
15

使用 gcc 查找您的代码。

int main()
{
     std::ifstream file("numbers.txt");
     if (file) 
     {
        cout << "Managed to read file successfully. \n";
        int x, y;
        file >> x >> y;

        cout << "Num 1: " << x << endl;
        cout << "Num 2: " << y << endl;
    }
    else
    {
        cout << "Unable to read file.";
    }
    return 0;
}

Answer 2

上面的代码会打印你的操作状态，如果你想读取和显示内容，你必须这样编写代码：

#include<iostream>
#include<fstream>

using namespace std;         

int main()    
{
            ifstream stream1("D:\\file1.txt");    
            char a[80];

            if(!stream1)    
            {
                        cout << "While opening a file an error is encountered" << endl;    
            }    
            else    
            {    
                        cout << "File is successfully opened" << endl;    
            }

            while(!stream1.eof())    
            {    
                        stream1 >> a;    
                        cout << a << endl;    
            }

            return(0);    
}