Generates a pseudorandom number.
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.
Requirements
| Routine | Required header | Compatibility |
| rand | <stdlib.h> | ANSI, Win 98, Win Me, Win NT, Win 2000, Win XP |
For additional compatibility information, see Compatibility in the Introduction.
Libraries
All versions of the C run-time libraries.
Example
// crt_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>
int 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() );
} Sample Output
19430
28222
9710
12070
7513
9501
1767
26041
11872
4097 See Also
Floating-Point Support Routines | srand | Run-Time Routines and .NET Framework Equivalents