rand

The rand function is used to generate the random numbers.

It is best to refer to the original documentation for a thorough and complete description of these functions.
The information is duplicated here for your convenience from the Microsoft Developers Network Library from Microsoft's Visual Studio 6.0.
Library Title: MSDN Library - January 1999 Release

It can be found through one of Microsoft's many internet web sites: http://msdn.microsoft.com

rand

Generates a pseudorandom number.

int rand( void );

Routine	Required Header	Compatibility
rand	<stdlib.h>	ANSI, Win 95, Win NT

For additional compatibility information, see Compatibility in the Introduction.

Libraries

LIBC.LIB	Single thread static library, retail version
LIBCMT.LIB	Multithread static library, retail version
MSVCRT.LIB	Import library for MSVCRT.DLL, retail version

Return Value

rand returns a pseudorandom number, as described above. There is no error return.

Remarks

The rand function returns a pseudorandom integer in the range 0 to RAND_MAX. Use the srand function to seed the pseudorandom-number generator before calling rand.

Example

/* RAND.C: This program seeds the random-number generator
 * with the time, then displays 10 random integers.
 */

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

void main( void )
{
   int i;

   /* Seed the random-number generator with current time so that
    * the numbers will be different every time we run.
    */
   srand( (unsigned)time( NULL ) );

   /* Display 10 numbers. */
   for( i = 0;   i < 10;i++ )
      printf( "  %6d\n", rand() );
}

Output