I need help using the rand() function

First of all yes I read the function on this site. That was console app, this is win32/directx. Ok what I want to do is generate a random number and assign it to the X1 coordinate of a rectangle, you know to blits and image.

I have tried several things and none seem to work.

First off I have a Meteor Class.

and I am assinging the X1 values to the rectangle via the member function

EnemyMeteor.SetX1Coordinate(); where EnemyMeteor is a meteor object.

I have trie doing this

int RandomX1=rand()%745;

EnemyMeteor.SetX1Coordinate(RandomX1);

or


EnemyMeteor.SetX1Coordinate(rand()%745);

yes and I am included #include <stdlib.h> This is my first time really using this function......please help.

Do you get a compiler error, does it not function properly or what? If the problem is that rand always gets the same numbers, then you need to seed it. If the problem is something else, you'll have to give more info abput it.

To learn more about rand() and seeding it etc. go here

>That was console app, this is win32/directx

Therefore there is a difference in how information is displayed which has absolutely nothing to do with the rand() function.

What's the problem? Is your code producing errors? If so, what errors? Is your code behaving in an unexpected manner? If so, why isn't it behaving as you expect?

In the absense of this info I'm going to take a wild stab in the dark. Have you seeded the random number generator with srand()?

Quote:

---

Originally posted by ninja
Do you get a compiler error, does it not function properly or what? If the problem is that rand always gets the same numbers, then you need to seed it. If the problem is something else, you'll have to give more info abput it.

To learn more about rand() and seeding it etc. go here

---

yeah seems to always have the same number.......

Don't really know what this "seeding" thing is all about......

it always get the same number about 50 or so.

Ok I am seeding with Time


srand(time(NULL));
int RandomX1;
RandomX1=rand()&500+100;

EnemyMeteor.SetX1Coordinate(RandomX1);


But maybe because this is using the time when randomization are not, well the numbers don't seem to be apart enough. I need good randomization for pixels between 0 and 800 pixels or so. What could I do? I am using MSVC++

or you could just use randomize().

eg.

type function()
{
int x1;
randomize();
x1 = (rand()%750)+1;

return type;
}

I too need something to give more random of numbers. I seed my rand() with srand(unsigned(time(NULL))), and I use my own function I made to work with rand

Code:

---

int random(int lowNumber, int HiNumber)
{
  return lowNumber + (rand() % HiNumber);
}

---

it works fine, it comes up with random numbers and all. The only problem I got with it, is the numbers aren't random enough. I am making a Vertical shooter with Allegro 4.01, and I just started the AI. I am using a Finite State Machine based on a switch statement. It works and compiles right, but all the enemies do just about the same thing all the time, because the numbers aren't coming up random enough.

Quote:

---

Originally posted by frenchfry164
I too need something to give more random of numbers. I seed my rand() with srand(unsigned(time(NULL))), and I use my own function I made to work with rand

Code:

---

int random(int lowNumber, int HiNumber)
{
  return lowNumber + (rand() % HiNumber);
}

---

it works fine, it comes up with random numbers and all. The only problem I got with it, is the numbers aren't random enough. I am making a Vertical shooter with Allegro 4.01, and I just started the AI. I am using a Finite State Machine based on a switch statement. It works and compiles right, but all the enemies do just about the same thing all the time, because the numbers aren't coming up random enough.

---

hehe yup sounds like the problem I am having. :)

Quote:

---

Originally posted by The Dog
or you could just use randomize().

eg.

type function()
{
int x1;
randomize();
x1 = (rand()%750)+1;

return type;
}

---

I am not sure if MSVC++ allows the use of randomize. I doesn't seem to work for me.

but try to place the seed-code elsewhere. I've had the problems you're having and sometimes solved it by placing the seed somewhere else. Hope that helps...

1.) http://www.cprogramming.com/cboard/s...threadid=18354

2.) Use the <cstdlib> library instead of <stdlib.h>

that link doesn't help at all.

I just need a way to make the numbers more random. It would work for something like ErionD's fighting game, where AI is only applied to one thing at a time, but in mine, over 20 things are applied, and they all do the same thing at the same time almost!

If you repeatedly seed the number generator with the time just before you generate a random.. it's going to generate the same random number of that short period of time (until the time changes). Seed once at the start of your program, and that's it.

I already figured that out, but it still doesn't give me random enough of numbers. If you looked at my function, it doesn't seed in the function. I have the seed in main.