hello,
I would like to generate a random number. I have looked on google but the way I found (using rand and srand from stdlib.h) doesn't works.
I would like to generate a random number with two boundaries, say between 1 to 100.
How do I do that? Still I am waiting to receive a book, so I am forced to look online...
Thanks in advance.
FSX
i have found a solution for that before using the C compilers help menu..
there are some example programs there using random function.. just try it..
^__^
I have VC++ and the help only tells about classes. Otherwise I would have looked on it myself.Originally Posted by nhoda911
The random() function returns a value between 0 and RAND_MAX. And you need to include stdlib to use that...
you can use rand() function also...
Compilers can produce warnings - make the compiler programmers happy: Use them!
Please don't PM me for help - and no, I don't do help over instant messengers.
Using random() it gives error. Using rand() only gives 41. I am eternally confused you're right! This is what I have done later, following a C++ program found on cprogramming:
But it seems to depend on the seconds, so that the random number only changes after one second. Probably it is because of <time.h> which counts seconds. Is there a way to do that in milliseconds?Code:#include <stdio.h> #include <stdlib.h> #include <time.h> int main(void) { int random; srand((unsigned)time(NULL)); random = rand()%100; printf("random = %d", random); return 0; }
Last edited by fsx; 05-12-2009 at 04:53 AM.
Yes, srand() will be set to a number corresponding to current time, and since that is in seconds, it's won't change more than once a second.
However, if you want a SEQUENCE of numbers that vary a fair bit, then srand() will set the STARTING POINT, further calls to rand() will be picking different numbers [make a loop that produces 10 numbers in a row - and make sure you put the srand() call OUTSIDE the loop - your program should never call srand more than once, unless you SPECIFICALLY ARE looking to repeate the same sequence of random numbers - e.g. for simulation using different algorithms to compare the results of the same sequence of random numbers].
--
Mats
Compilers can produce warnings - make the compiler programmers happy: Use them!
Please don't PM me for help - and no, I don't do help over instant messengers.
Well this is great, now it works! =) Thanks so much Matsp! =)
