#include <stdio.h>
  int sprintf( char *buffer, const char *format, ... );

The sprintf() function is just like printf(), except that the output is sent to buffer. The return value is the number of characters written. For example:

   char string[50];
   int file_number = 0;         

   sprintf( string, "file.%d", file_number );
   output_file = fopen( string, "w" );                

Note that sprintf() does the opposite of a function like (Standard C String and Character) atoi() -- where (Standard C String and Character) atoi() converts a string into a number, sprintf() can be used to convert a number into a string.

For example, the following code uses sprintf() to convert an integer into a string of characters:

   char result[100];
   int num=24;
   sprintf( result, "%d", num );