使用EOF终结器与.empty（）函数获取相同的输入
我想获取用户输入，并且给出的字符数很重要。我通过input.empty（）获得了令人满意的结果，但是在我按Enter后终止。我希望它在我专门键入ctrl+d之后终止。
1) do{ 2) while(std::getline(std::cin, input)){
getline(std::cin, input); buffer += input;
buffer += input; buffer += '\n';
buffer += '\n'; }
}while(!input.empty()); std::cin.ignore();
除了Enter终结器外，第一个代码按照我的要求工作，第二个代码具有更多的字符，我不确定它的确是什么，但是当我键入ctrl+d 。 输入和缓冲区均为std :: String。因此，如何获得与input.empty（）的相同结果。
先感谢您。
I want to get user input, and the number of characters that are given is important. I get a satisfying result with input.empty() but it terminates after I press Enter. I want it to terminate after i specifically type Ctrl+D.
1) do{ 2) while(std::getline(std::cin, input)){
getline(std::cin, input); buffer += input;
buffer += input; buffer += '\n';
buffer += '\n'; }
}while(!input.empty()); std::cin.ignore();
Other than the Enter terminator the first code work as I want it to, and the second one has a character more, which I'm not sure what it exactly is, but it does end when I type Ctrl+D. input and buffer are both std::string. So how can I get the same result as input.empty().
Thank you in advance.
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在您的问题中，您声称第二个代码片段在
buffer中比第一个代码段产生的字符更多。但是，我认为此语句是错误的。由于以下原因，这是第一个应该具有更多字符的角色：std :: getline至少读取一个字符后遇到文件结束，那么两个代码段都将表现相同方式。但是，如果
std :: getline在阅读至少一个字符之前遇到文件结束（即，如果在行开始时遇到了一个字符），则两个代码段的行为是不同的：第一个代码片段将在终止循环之前将附加的newline字符写入buffer，而第二个代码段将立即终止。换句话说，第一个代码段产生的字符太多，因为它的逻辑是错误的。因此，我建议您使用第二个片段。但是，目前尚不清楚第二个代码段中应该完成的
std :: cin.ignore（）;，因为函数std :: getline已经删除了输入流（如果存在）的newline字符。另外，调用std :: ignore在已经达到流的结束时可能没有效果。因此，您可能应该删除该线路。In your question, you claim that the second code snippet produces one character more in
bufferthan the first code snippet. However, I assume that this statement is false. It is the first one which should have one character more, for the following reason:When
std::getlineencounters end-of-file after reading at least one character, then both code snippets will behave the same way.However, if
std::getlineencounters end-of-file before reading at least one character (i.e. if it is encountered at the start of the line), then the behavior of the two code snippets is different: The first code snippet will write an additional newline character tobuffer, before the loop gets terminated, whereas the second code snippet will terminate immediately.In other words, the first code snippet produces one character too much, because its logic is wrong. Therefore, I suggest that you use the second snippet. However, it is unclear what
std::cin.ignore();in the second code snippet is supposed to accomplish, because the functionstd::getlinehas already removed the newline character from the input stream (if it existed). Also, callingstd::ignorewhen the end of the stream has already been reached will probably have no effect. Therefore, you should probably remove that line.