Re: Random int giving only 0

From:

Pete Becker <pete@versatilecoding.com>

Newsgroups:

comp.lang.c++

Date:

Thu, 5 May 2011 09:49:50 -0400

Message-ID:

<2011050509495067590-pete@versatilecodingcom>

On 2011-05-05 09:08:15 -0400, Huub said:

On Thu, 05 May 2011 08:20:24 +0000, Jorgen Grahn wrote:

On Thu, 2011-05-05, Huub wrote:

Hi,

I have a problem using rand().

I've been trying to use it in 4 different ways: rand(), rand() % n,
rand () % n-1 and rand() % (high - low + 1) + low with high = 22 and
low = 1. Since rand() is pseudo-random, the results should show a
returning pattern. However, though it works fine in a little rand()
test program giving up to 8 different outcomes, in my real code using
either way, the only outcome I get is 0. Any idea about the cause of
this?

I'd say you are either mistaken (rand() returns other numbers, but you
lose them in your manipulations) or you have defined your own rand()
which is the one that really gets called.

/Jorgen

OK, can't get it working. This is the code:

in class Robot:

int Robot::Xpos(int& x)
{
x = rand(); //gives e.g.: x = 22
return 0
}

in main(): (with Robot = robot)

x_pos = robot.Xpos(x) // gives 0

What am I doing wrong here that the value of 22 isn't passed from Xpos ?\

Please post complete code that illustrates the problem. This code
doesn't declare x or x_pos, nor does it test their values, so it's
difficult to say what's happening. But one thing is clear: the value of
x_pos after this call will be 0, because that's what Robot::Xpos
returns.

--
Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The
Standard C++ Library Extensions: a Tutorial and Reference
(www.petebecker.com/tr1book)