c++filesizefstreamistream

Using C++ filestreams (fstream), how can you determine the size of a file?

I'm sure I've just missed this in the manual, but how do you determine the size of a file (in bytes) using C++'s istream class from the fstream header?

Solution

  • You can seek until the end, then compute the difference:

    std::streampos fileSize( const char* filePath ){

    std::streampos fsize = 0;
    std::ifstream file( filePath, std::ios::binary );

    fsize = file.tellg();
    file.seekg( 0, std::ios::end );
    fsize = file.tellg() - fsize;
    file.close();

    return fsize;
}