srand

The srand 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

srand

Sets a random starting point.

void srand( unsigned int seed );

Routine	Required Header	Compatibility
srand	<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

None

Parameter

seed

Seed for random-number generation

Remarks

The srand function sets the starting point for generating a series of pseudorandom integers. To reinitialize the generator, use 1 as the seed argument. Any other value for seed sets the generator to a random starting point. rand retrieves the pseudorandom numbers that are generated. Calling rand before any call to srand generates the same sequence as calling srand with seed passed as 1.

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