putc
Syntax:
  #include <cstdio>
  int putc( int ch, FILE *stream );

The putc() function writes the character ch to stream. The return value is the character written, or EOF if there is an error. For example:

   int ch;
   FILE
*input, *output;
   input
= fopen( "tmp.c", "r" );
   output
= fopen( "tmpCopy.c", "w" );
   ch
= getc( input );
   
while( ch != EOF ) {
     putc
( ch, output );
     ch
= getc( input );
   
}
   fclose
( input );
   fclose
( output );            

generates a copy of the file tmp.c called tmpCopy.c.