使用 Ubuntu gedit 寫入文件

Question

我正在嘗試編寫一個簡單的程序來寫入已經存在的文件。 我收到此錯誤：

hello2.txt: file not recognized: File truncated
collect2: ld returned 1 exit status

我究竟做錯了什么？ （我嘗試了兩種方式的斜線，但我仍然得到同樣的錯誤。）

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

int main()
{
    ofstream outStream;
    outStream.open(hello3.txt);
    outStream<<"testing";
    outStream.close;

    return 0;
}

Answer 1

其中有兩個錯誤：

1. hello3.txt 是一個字符串，因此應該用引號引起來。

2. std::ofstream::close() 是 function，因此需要括號。

更正后的代碼如下所示：

#include <iostream>
#include <fstream>

int main()
{
    using namespace std; // doing this globally is considered bad practice.
        // in a function (=> locally) it is fine though.

    ofstream outStream;
    outStream.open("hello3.txt");
    // alternative: ofstream outStream("hello3.txt");

    outStream << "testing";
    outStream.close(); // not really necessary, as the file will get
        // closed when outStream goes out of scope and is therefore destructed.

    return 0;
}

請注意：此代碼會覆蓋該文件中以前的任何內容。