C++ Rewrite a file but leaving out everything before a word

Question

I\'m using Visual C++ Express 2010... and I\'m very new to C++.

I want to read a file then remove everything before the word \"<--START-->\" and rewrite the file

Answer 1

std::string file_contents = LoadFileAsString("text.txt");
std::string::size_type offset = file_contents.find("<--START-->");
std::ofstream("text.txt") << file_contents.c_str() + offset;

With LoadFileAsString defined like this:

std::string LoadFileAsString(const std::string & fn)
{
    std::ifstream fin(fn.c_str());

    if(!fin)
    {
        std::string what = "LoadFileAsString() : Failed to open file \"";
        what += fn + '\"';
        throw std::runtime_error(what);
    }

    std::ostringstream oss;
    oss << fin.rdbuf();

    return oss.str();
}