c++ - 从 ifstream 读取时出现多余的空行

Question

在我的程序中，我已重定向标准输出以打印到文件“console.txt”。一个函数像这样写入该文件:

void printToConsole(const std::string& text, const TCODColor& fc, const TCODColor& bc)
    {
        // write the string
        cout << text << "@";

        // write the two color values
        cout << static_cast<int>(fc.r) << " "
             << static_cast<int>(fc.g) << " " 
             << static_cast<int>(fc.b) << " "
             << static_cast<int>(bc.r) << " "
             << static_cast<int>(bc.g) << " " 
             << static_cast<int>(bc.b) << " " << endl;
    }

我有一个从该文件中读取的函数，如下所示:

   void Console::readLogFile()
   {
        ifstream log("console.txt", ifstream::in);
        if(!log.is_open())
        {
            cerr << "ERROR: console.txt not found!" << endl;
            return;
        }

        // read new input into the stack
        char str[256];
        while(!log.eof())
        {
            log.getline(str, 256);
            cerr << "str: " << str << endl;
            stk.push(static_cast<string>(str));
            // stk is a std::stack<std::string> member of the class this function
            // belongs to.
        }
        cerr << endl;

        /* Do some stuff with str and stk here */

        log.close();
        clearLogFile();
    }

    void Console::clearLogFile()
    {
        FILE* log;
        log = fopen("console.txt", "w");
        fclose(log);
    }

调用 readLogFile 时，console.txt 通常为空。我希望 while(!log.eof()) 循环在那种情况下永远不会执行，但它会执行。文件中总是至少有一个多余的空行，有时有两个，当从文件中读取输入时，输入行夹在两个空行之间。调用此函数几次后，while(!log.eof()) 循环进入无限循环，从文件中提取空行。该程序的典型运行过程如下所示:

str: 

str: Player moved.@191 191 191 0 0 0
str: 

str: 
str: Player moved.@191 191 191 0 0 0 
str: 

str: // there should be a 'Player moved.' line in here
str:

str: // here as well
str:

str: // also here
str:

str: 
str: Player moved.@191 191 191 0 0 0 
str: 

str:
str:
str:
str:
str:
str:
(onto infinite loop)

谁能看出我在这里做错了什么？

编辑:正如 Amardeep 所建议的，我将 while(!log.eof()) 循环更改为 do{...}while(!log.fail);循环。这解决了无限循环问题，但没有解决多余的行。该程序的行为与以前一样，除了它曾经进入无限循环的地方，它现在只读取它应该读取输入的空白​​行，如下所示:

str:

str:

str:

str: 
(etc.)

Answer 1

eof() 状态在您尝试读取之前不会设置。您应该更改读取循环以执行 getline() 然后检查 fail() 状态，而不是依赖 eof()，这不涵盖尝试读取文件时可能出错的范围。