root@ozdaltx.UUCP (root) (11/16/89)
I am trying to write some code to generate a random number that would
fall between 0 and 65,000. I know there is something I'm missing
here, but can't seem to pin it down. I feel like the problem is in
the type declarations, but have tried most combinations with not a lot
of success. Any suggestions?
Sample code:
------------------------------
#include <stdio.h>
main()
{
extern unsigned short rand();
extern unsigned long time();
unsigned short offset;
/* generate a random number using time and pid as seed */
while(1){
srand((unsigned)getpid() + (unsigned)time(NULL));
offset = rand();
printf("NUMBER=%ld\n",offset);
sleep(1);
}
}
------------------
Thanks
Scotty
AIDS INFORMATION EXCHANGE BBS (214) 247-2367/247-5609
"Education is the best weapon"
{ames,rutgers,texsun,smu}!attctc!ozdaltx!sysop mike@relgyro.stanford.edu (Mike Macgirvin) (11/17/89)
In article <5726@ozdaltx.UUCP> root@ozdaltx.UUCP (root) writes: >I am trying to write some code to generate a random number that would >fall between 0 and 65,000. I know there is something I'm missing >#include <stdio.h> >main() >{ > extern unsigned short rand(); > extern unsigned long time(); > unsigned short offset; > while(1){ > srand((unsigned)getpid() + (unsigned)time(NULL)); > offset = rand(); > printf("NUMBER=%ld\n",offset); ^ > sleep(1); > } >} "%ld" means long int. 'offset' is a short int. You said so. I believe the behaviour you are seeking requires "%ud". Now I have to type in a bunch of junk for the line counter.. hit 'n' to avoid it. . . . . . . . . . . ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ + Mike Macgirvin Relativity Gyroscope Experiment (GP-B) + + mike@relgyro.stanford.edu (36.64.0.50) + ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
rhg@cpsolv.UUCP (Richard H. Gumpertz) (11/17/89)
In article <5726@ozdaltx.UUCP> root@ozdaltx.UUCP (root) writes: > extern unsigned short rand(); rand returns int. If int != short in your implementation, that could account for your problems. -- =============================================================================== | Richard H. Gumpertz rhg%cpsolv@uunet.uu.NET -or- ...uunet!amgraf!cpsolv!rhg | | Computer Problem Solving, 8905 Mohawk Lane, Leawood, Kansas 66206-1749 | ===============================================================================
root@ozdaltx.UUCP (root) (11/22/89)
I wish to say thanks to the many net.replys on this question. Sorry I can't e-mail individual thanks to everyone. Although the example I gave was not very good, the answers I received back opened a few doors for me in the deeper workings of C. Learn something new every day. Scotty
kenmoore@unix.cis.pitt.edu (Kenneth L Moore) (11/28/89)
In article <5726@ozdaltx.UUCP> root@ozdaltx.UUCP (root) writes: >I am trying to write some code to generate a random number that would >fall between 0 and 65,000. >------------------ >Thanks >Scotty >AIDS INFORMATION EXCHANGE BBS (214) 247-2367/247-5609 > "Education is the best weapon" > {ames,rutgers,texsun,smu}!attctc!ozdaltx!sysop Here is a program that will generate the numbers you need. To change the range of responses just change the 65000 in the subroutine. The ran48 is seeded with the time and a static multiplier is used for when the calls are so close that system time has not changed. X-----X-----X-----X-----X-----X cut here X-----X-----X-----X-----X-----X-----X #include <time.h> main() { long timeofday; int ind,test,num1; timeofday = time(0); printf("\n The time is: \n %s\n",ctime(&timeofday)); ind = 0; while(ind++ != 15) { num1 = sixtyfive(); printf(" The number is %d \n",num1); } } int sixtyfive() { static int xxx; long seedval; double drand48(),x; int num; seedval = time(0)+(long)xxx; srand48(seedval); xxx = seedval*drand48(); x = drand48(); num = (int)(65000*x); return(num); } Sign me: KK KK EEEEEEEE NN NN MM MM OOOOO OOOOO RRRRRR EEEEEEEE KK KK EEEEEEEE NNN NN MMM MMM OOOOOOO OOOOOOO RR RR EEEEEEEE KK KK EE NNNN NN MMMM MMMM OO OO OO OO RR RR EE KKKKK EEEEE NN NN NN MM MM MM MM OO OO OO OO RRRRR EEEEE KKKKK EEEEE NN NN NN MM MMM MM OO OO OO OO RR RR EEEEE KK KK EE NN NNNN MM M MM OO OO OO OO RR RR EE KK KK EEEEEEEE NN NNN MM MM OOOOOOO OOOOOOO RR RR EEEEEEEE KK KK EEEEEEEE NN NN MM MM OOOOO OOOOO RR RR EEEEEEEE kenmoore@unix.cis.pitt.edu (Kenneth L. Moore) (Sorry about the long sig but inews won't recognise my .signature... even with "chmod 777 .signature". Tsk. Tsk.)