How to create random integers in a given range in c programming

Richa Bansal · 01-23-2013, 08:37 AM

How to create random integers in a given range in c programming.
Thanks

acid_kewpie · 01-23-2013, 08:39 AM

https://www.google.co.uk/search?q=Ho...+c+programming

You migth want to say please / thank you in future when asking for help, and state more than a title in your post.

theNbomr · 01-23-2013, 09:35 AM

man 3 rand
man 3 random

Use a multiplier to scale the result.

--- rod.

H_TeXMeX_H · 01-23-2013, 11:30 AM

Another question would be: how random ?

Unseeded rand will give you the same number every time. How do you plan on seeding it, and how random do the numbers need to be ?

Tryptophan · 01-26-2013, 08:06 AM

Well, you can simulate a random number... If you're able to use a function which gives you the amount of seconds of a time period, you can take that last number, knowing that will oscillate in a big way, and use it as a random.

yahoosam · 02-12-2013, 12:55 AM

Try this :
...
int num;
unsigned int iseed = (unsigned int)time(NULL);
srand (iseed);
num = rand ();
...

sundialsvcs · 02-12-2013, 01:51 PM

Be careful about seeding the PRNG ... most of the time, the runtime library has already done this, and you don't want to re-seed unless you need a repeatable sequence.

There are, generally, two flavors of PRNG (= Pseudo Random-Number Generator) functions. One flavor produces a known-positive integer.   Simply use the modulo operator to clip that to the desired range. Another flavor produces a floating-point number in the range [0..1]. Simply multiply this value, and truncate to an integer.