读写文件流C++

Reading and Writing Filestreams C++

本文关键字：C++ 文件 读写      更新时间：2023-10-16

我在将用户输入保存到Txt文件中时遇到问题。不确定我做错了什么；它没有写入文件：

void Menu::nowShowingDecisions()
{
    switch (userInput)
    {
    case 1:
        system("cls");
        xyPosition(0, 0);
        CAtitleHeader();
        CAtitleMenu();
        getUserInput();
        CAtitleDecisions();
        break;
        return;
    case 2:
    {
        string userName;
        string password;
        {
            ofstream outFile;
            {
                outFile.open("C:\Test\Test.txt");
                if (!outFile.good())
                    cout << "File Could Not Be Opened." << endl;
                else
                {
                    cout << "Enter Username:";
                    cin >> userName;
                    cout << "Enter Password:";
                    cin >> password;
                    while (cin >> userName >> password)
                        outFile << userName << password << endl;
                    outFile.close();
                }
            }
        }
        return;
        {
            const int COL_SZ = 10;
            ifstream inFile;
            inFile.open("C:\Test\Test.txt");
            if (!inFile.good())
                cout << "File could not be opened" << endl;
            else
            {
                cout << left;
                cout << "Movie Ticket Accounts" << endl;
                cout << setw(COL_SZ) << "User Name" << setw(COL_SZ) << "Password" << endl;
                while (inFile >> userName >> password)
                {
                    cout << setw(COL_SZ) << userName << setw(COL_SZ) <<
                    password << setw(COL_SZ) << endl;
                }
                inFile.close();
                return;
            }
        }
    }
    break;

在这个代码块中

             cout << "Enter Username:";
              cin >> userName;             // BEING IGNORED
              cout << "Enter Password:";
              cin >> password;             // BEING IGNORED
              while (cin >> userName >> password) // THIS IS BEING SAVED>
                  outFile << userName << password << endl;

您没有将第一个userName和password写入输出文件。

目前还不清楚您是否真的想在其中包含while循环。如果你只想写出第一个用户名和密码，你需要将其更改为：

              cout << "Enter Username:";
              cin >> userName;
              cout << "Enter Password:";
              cin >> password;
              if (cin) 
                  outFile << userName << password << endl;

使用C++读取或写入txt可以用这样一种简单的方式完成。

//在文本文件上书写

 #include <iostream>
 #include <fstream>
 using namespace std;
 int main () 
 {
   ofstream myfile ("example.txt");
    if (myfile.is_open())
 {
    myfile << "This is a line.n";
    myfile << "This is another line.n";
   myfile.close();
 }
   else cout << "Unable to open file";
    return 0;
}

//读取文本文件

 #include <iostream>
 #include <fstream>
 #include <string>
 using namespace std;
 int main () 
 {
   string line;
   ifstream myfile ("example.txt");
  if (myfile.is_open())
  {
    while ( getline (myfile,line) )
   {
      cout << line << 'n';
    }
  myfile.close();
 }
  else cout << "Unable to open file"; 
 return 0;
 }
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