What is fopen() function ?

• It creates a new file for use
• Open an existing file for use
• It include file name, data structure, and mode (purpose)
• File name is string of characters that make up a valid file name for the operating system.
• The file name may contain two parts, first primary name and second is optional part, second part is extension part like as help.txt, program.c etc.
• The data structure of a file is defined as FILE in the library of standard I/O function definitions.
• All files should be declared as type FILE before they are used.
• The FILE is a defined data type.
• The mode or purpose means what we do with the file.

Syntax:

FILE *file_pointer;

file_pointer =  fopen (“ file_name”, “ mode”);

ex:

     FILE*fp;

     fp = fopen (“help”,”w”);