Mail Archives: djgpp/2007/08/30/17:01:19
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From: | "MikeC" <My_address AT end DOT of DOT post>
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Newsgroups: | comp.os.msdos.djgpp
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Subject: | random() : What am I doing wrong?
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Message-ID: | <N1GBi.41236$S91.9560@newsfe7-win.ntli.net>
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Date: | Thu, 30 Aug 2007 20:47:41 GMT
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To: | djgpp AT delorie DOT com
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DJ-Gateway: | from newsgroup comp.os.msdos.djgpp
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Reply-To: | djgpp AT delorie DOT com
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Folks,
Here's an open invitation to make me feel foolish!
Here's the program :
#include <time.h>
#include <stdlib.h>
main()
{ long lng;
lng = rawclock();
printf("\nClock = %ld - ", lng);
srand(lng);
printf("Random numbers = %ld; %ld; %ld",random(),random(),random());
}
The idea is to seed the random number generator from the clock, so that the
first call to random() will always produce a different result.
When I run the program several times, here's what it yields :
Clock = 1392294 - Random numbers = 1027100827; 143302914; 2078917053
Clock = 1393105 - Random numbers = 1027100827; 143302914; 2078917053
Clock = 1393314 - Random numbers = 1027100827; 143302914; 2078917053
Clock = 1393420 - Random numbers = 1027100827; 143302914; 2078917053
Clock = 1393471 - Random numbers = 1027100827; 143302914; 2078917053
Clock = 1393512 - Random numbers = 1027100827; 143302914; 2078917053
Clock = 1393548 - Random numbers = 1027100827; 143302914; 2078917053
The 'random' numbers are the same every time I run the program, yet they are
being seeded be a clock value that is different each time. I guess the wood
is there somewhere, but the trees are getting in the way.
Incidentally, I'm running Windows 2000, SP4.
Advance thanks,
MikeC.
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