I can't add a new line to c++ string

问题

How do you add a new line to a c++ string? I'm trying to read a file but when I try to append '\n' it doesn't work.

std::string m_strFileData;
while( DataBegin != DataEnd ) {
    m_strFileData += *DataBegin;
    m_strFileData += '\n';
    DataBegin++;
}

回答1:

If you have a lot of lines to process, using stringstream could be more efficient.

ostringstream lines;

lines << "Line 1" << endl;
lines << "Line 2" << endl;

cout << lines.str();   // .str() is a string

Output:

Line 1
Line 2

回答2:

Sorry about the late answer, but I had a similar problem until I realised that the Visual Studio 2010 char* visualiser ignores \r and \n characters. They are completely ommitted from it.

Note: By visualiser I mean what you see when you hover over a char* (or string).

回答3:

This would append a newline after each character, or string depending on what type DataBegin actually is. Your problem does not lie in you given code example. It would be more useful if you give your expected and actual results, and the datatypes of the variables use.

回答4:

Just a guess, but perhaps you should change the character to a string:

 m_strFileData += '\n';

to be this:

 m_strFileData += "\n";

回答5:

Try this:

ifstream inFile;
inFile.open(filename);
std::string entireString = "";
std::string line;

while (getline(inFile,line))
{
   entireString.append(line);
   entireString.append("\n");
}

来源：https://stackoverflow.com/questions/4128077/i-cant-add-a-new-line-to-c-string