Question

为什么我不能用这个打印的文件中的每一行？它什么也没输出。

    string line;
    ifstream s {"book_list.txt"};
    while (getline(s, line)) {
        cout << line << endl;
    }

我已经包含了fstream，sstream，string，stdio.h，stdlib.h以及我正在使用命名空间std;

Answer 1

#include<iostream>
#include<fstream>
#include<string>
using namespace std

int main()
{
    string line;
    ifstream s ("book_list.txt");
    if (s.is_open())
    {
        while ( getline (s,line) )
        {
            cout << line << endl;
        }
        s.close();    // Don't forget to close the file
    }
    else
        cout << "Unable to open file";
    return 0;
}

我跳起来有帮助。

Answer 2

我猜文件不存在。请查看：

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或

if(!s.good()) {
    // error
}

Answer 3

你应该这样做：

ngOnDestroy(): void {
  this.changes.disconnect();
}

Answer 4

#include <iostream>
#include <fsstream>
using namespace std;
int main()
{
    string data;
    int counter = 0;
    ifstream infile("test_file.txt");
    while (!infile.eof()){
        getline(infile , data);
        counter += 1;
    }
    cout << "The number of lines is : " << counter << endl;
    return 0;
}

Answer 5

#include <iostream>
#include <fsstream>
using namespace std;
int main()
{
    string info;
    int counter = 0;
    ifstream file("test_file.txt");
    while (!file.eof()){
        getline(file , info);
        counter += 1;
    }
    cout << "The number of lines is : " << counter << endl;
    return 0;
}

用C ++读取文件中的行

5 个答案: