Thread: Rand() function

Hi.
Im looking for a simpley way to pick randomly one of thease numbers:
1-2-3-4.

I have searched on google, but finds nothing but how to get a randomnumber between 0 and some stupid max-number!

You could have always just read the FAQ entry on the subject.

[edit]
On an aside, did you never think to just simply add one to the number, since you know it starts at zero, and you want it to start at one? I hope you don't have to ask again when you want to generate a number starting at 2. Or 3. Or again at 4...
[/edit]

Quzah.

To answer your next question.. you probably forgot to seed your random number generator.

Code:

srand(unsigned(time( ));

This is to be done only once.

To answer your next next question, you'll need a set of parenthesis around that unsigned, like this for it to actually work:

Code:

srand( (unsigned) time( ) );

Oh, and of course you'll actually have to provide a value to the time function. So you really end up with something like this:

Code:

srand( (unsigned) time( 0 ) );

Or, you could have just read the FAQ as I suggested, which covers srand.

Quzah.

Originally Posted by Da-Nuka

Hi.
Im looking for a simpley way to pick randomly one of thease numbers:
1-2-3-4.

I have searched on google, but finds nothing but how to get a randomnumber between 0 and some stupid max-number!

Then obviously you don't know what a max number is *cough* 4 is your max number for the sequent 1-2-3-4 */cough*. It's not brain surgery...and as Quzah said, the FAQ is god...

And you can't forget that time_t isn't guaranteed to be convertible to unsigned int:

Code:

unsigned int random_seed()
{
  unsigned int seed(0);
  time_t now = time(0);
  unsigned char *p = reinterpret_cast<unsigned char *>(&now);

  for (size_t i = 0; i < sizeof now; i++)
    seed = seed * (numeric_limits<unsigned char>::max() + 2U) + p[i];

  return seed;
}

...

srand(random_seed());

Im not that noob
Just lazy!

All I needed was the function name... (first post)

And I feel I gotta defend my self a little:
I wasnt talking about 4 as the max number, if I had found ways to do that, the problem had been solved.

The maxnumber I allways bumbed into was RAND_MAX.

A example:
http://www.phim.unibe.ch/comp_doc/c_...IONS/rand.html

>Just lazy!
That's a bad kind of lazy.

>I wasnt talking about 4 as the max number, if I had found ways to do that, the problem had been solved.
I don't understand. How is "get a randomnumber between 0 and some stupid max-number!" different from what you want? Unless you want a random permutation, what you've been finding is a viable solution. Give us more detail as to what you're trying to do.