C++ 检查 string::getline 中的 eof
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原文地址: http://stackoverflow.com/questions/2251433/
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checking for eof in string::getline
提问by assassin
How do I check for end-of-file using the std::getlinefunction? If I use eof()it won't signal eofuntil I attempt to read beyond end-of-file.
如何使用该std::getline函数检查文件结尾？如果我使用eof()它，eof直到我尝试读取文件末尾之外，它才会发出信号。
回答by AProgrammer
The canonical reading loop in C++ is:
C++ 中的规范阅读循环是：
while (getline(cin, str)) {
}
if (cin.bad()) {
// IO error
} else if (!cin.eof()) {
// format error (not possible with getline but possible with operator>>)
} else {
// format error (not possible with getline but possible with operator>>)
// or end of file (can't make the difference)
}
回答by Manuel
Just read and then check that the read operation succeeded:
只需读取然后检查读取操作是否成功：
std::getline(std::cin, str);
if(!std::cin)
{
std::cout << "failure\n";
}
Since the failure may be due to a number of causes, you can use the eofmember function to see it what happened was actually EOF:
由于失败可能是由多种原因造成的，您可以使用eof成员函数来查看实际发生的 EOF：
std::getline(std::cin, str);
if(!std::cin)
{
if(std::cin.eof())
std::cout << "EOF\n";
else
std::cout << "other failure\n";
}
getlinereturns the stream so you can write more compactly:
getline返回流，以便您可以更紧凑地编写：
if(!std::getline(std::cin, str))
