use fstream read & write

 

I want to read someinfo from a file, and write someinfo into the file; there will be redundancy info in the file, if the length of writted info less than the length of original file info.

 

workaround:

open with std::fstream::in

then

open with std::fstream::trunc

 

 

 

std::fstream fs(fileName, std::fstream::in | std::fstream::out);
char cArray[256];
fs.getline(cArray,256);
fs.close();

std::fstream fsw(fileName, std::fstream::trunc | std::fstream::out);
//fs.seekg(std::ios_base::beg);

fsw.write(totalStr.c_str(), totalStr.size());
fsw.close();