Question

我试图在一个文件中打印3行，但最终发生的是打印所有3个点中的1行，打印所有3个点中的第2行，然后，你猜对了，与第3名相同。我想让它按一下按钮打印出所有3行。

ifstream read_file;
 string fname, name;
 cout << "Type the complete address of the file you would like to open.\n";
 cin >> fname;
 system("cls");
 read_file.open(fname.c_str());

 while(getline(read_file, fname))

 {
if (fname == "")continue;

cout << "You had "<< fname << " health left\n";
cout << "You delt " << fname  << " damage\n";
cout << "There were " << fname << " enemies left\n";
system("pause");
}


 read_file.close();
 system("pause");

Answer 1

查看您的代码

while(getline(read_file, fname))   
{
    if (fname == "")
        continue;

    cout << "You had "<< fname << " health left\n";
    cout << "You delt " << fname  << " damage\n";
    cout << "There were " << fname << " enemies left\n";
    system("pause");
}

很明显，你只读了一行，并打印了三次 - 你在这些输出之间没有做任何事情fname。

我建议您停止重复使用同一个变量用于多种目的，这是许多错误的来源（以下假设没有空行。）

string health;
string damage;
string enemies;
while(getline(read_file, health) && getline(read_file, damage) && getline(read_file, enemies))   
{
    cout << "You had "<< health << " health left\n";
    cout << "You delt " << damage  << " damage\n";
    cout << "There were " << enemies << " enemies left\n";
}

如果文件中有空行，请考虑编写自己的跳过空行的getnonemptyline函数。

Answer 2

就像molbdnilo所说，你只是从文件中读取一行，然后尝试用它做三件事。如果你想继续重复使用相同的（奇怪名称）变量，你可以像

那样做

while(getline(read_file, fname)){
    if (fname == "")continue;
    cout << "You had "<< fname << " health left\n";
}

while(getline(read_file, fname)){
    if (fname == "")continue;
    cout << "You delt " << fname  << " damage\n";
}

while(getline(read_file, fname)){
    if (fname == "")continue;
    cout << "There were " << fname << " enemies left\n";
}

system("pause");

如何同时从文件中打印3行？

2 个答案: