Opening Text Stream and Binary Stream Files

Each text stream file and each binary stream file is represented by a file control structure of type file. This structure is initialized depending on the mode in which the file was opened. Unpredictable results might occur if you attempt to change the file control structure.

The format of fopen() is: 
#include <stdio.h>
FILE *fopen(const char *filename, const char *mode);

The mode variable is a character string that consists of an open mode which may be followed by keyword parameters. The open mode and keyword parameters must be separated by a comma or one or more blank characters.

To open a text stream file, use fopen() with one of the following modes:
  • r or r+
  • w or w+
  • a or a+
To open a binary stream file, use fopen() with one of the following modes:
  • rb,
  • rb+ , or r+b
  • wb,
  • wb+ or w+b
  • ab,
  • awb+ or a+b
C++ language only
To open a binary stream file, use the open() member function with ios::binary, or any of the following modes:
  • ios::app
  • ios::ate
  • ios::in
  • ios::out
  • ios::trunc