hellyeah | A chrome extension that upgrades your Facebook likes | Browser Plugin library

Use ios::trunc instead of ios::app

Using std::ios::app in the constructor for your std::ofstream tells the program to append to the file and not overwrite it. If you want to overwrite it (ie truncate), then using std::ios::trunc will tell the program to overwrite the existing file. ofstream does this by default, so you could just write the initialization as just std::ofstream newFile(filePath);.

Also, don't try to read the file and write to it at the same time; that won't work. Use ifstream to get the data into the buffer, then use close() to close the file. Then initialize newFile to overwrite the file and write out the buffer.