When you send output to a stream, the stream is supported with a
buffer and which may not trigger printing immediately. Buffering
allows to spool a large amount of output, facilitate the printer
to keep page formatting.
Forcing all buffered contents to actually be printed or
displayed the output on a screen, is known as "flushing" the
stream. A flush can be forced by calling the flush function
associated with each output stream.
for(int i=0; i < 4; i++)
myFile12<<": Adding text "<< i <<" " <<flush;