文件操作（OOP） [英] File Operations (OOP)

问题描述

if(choice ==3){
        string title = "";
        ofstream myfile ("shows.txt");
        if (myfile.is_open())
        {
            cout << "Enter the title of the new show: ";
            cin >> title;
            
            myfile << title << endl;
            myfile.close();
        }
        else cout << "Operation Failed";
  }

当我要求用户输入新节目的名称时，它会自动放在开头，覆盖第一行中的任何值。如何在文本文件的底部添加一个新行，然后将用户的输入添加到该行？

When I ask the user to enter the name of a new show, it iss automatically placed at the beginning, over-writing whatever value is in the first line. How do I add a new line at the bottom of the text file, then add the user's input to that line?

推荐答案

您需要寻找结束写入之前的文件，请参阅 http://www.cplusplus.com/reference/ostream/ostream/seekp/ [ ^ ]



所以你的电话会是这样的：

You need to seek to the end of the file before writing to it, see http://www.cplusplus.com/reference/ostream/ostream/seekp/[^]

So your call would look something like:

if (myfile.is_open())
        {
            myfile.seekp(0, ios_base::end);    //Seek to end of file.
            cout << "Enter the title of the new show: ";

或者，当您使用以下重载打开文件时，可以执行此操作：

Alternatively, you can do this when you open the file with the following overload:

std::ofstream myfile ("shows.txt", std::ofstream::app);

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