Random number generator

Hi,

Is there a quicker way of doing this bit of code.want to roll 5x ten sided dice and add the results.The way i have done it looks nasty,

Code:

int playerHealth=( (rand ()%10)+1)+( (rand ()%10)+1)+( (rand ()%10)+1)+( (rand ()%10)+1)+( (rand ()%10)+1);

Do i have name each roll as a varible and then add the results?tried

Code:

int playerHealth=( (rand ()%10)+1)*5

but that only rolls once and multiplys it by 5.

any ideas?

For convenience, I would put the dice roll in a function

Code:

int roll( int sides, int num_dice )
{
    int sum = 0;
    for( int i = 0; i < num_dice; ++i)
        sum += rand() &#37; sides + 1;

    return sum;
} 

/* ... */

int playerHealth = roll( 10, 5 );

(untested)

what about

Code:

int playerHealth=( rand ()%46)+5;

bit less random but same range.

Kurt

Originally Posted by ZuK

what about

Code:

int playerHealth=( rand ()%46)+5;

bit less random but same range.

Kurt

Actually, maybe a little too random - extreme' values would be more common, and the 'middle-road' values would occur less frequendly.. The distribution should be uneven (in theory) so that rolls with multiple die are typically biased towards the middle-road values.
(Ask anyone who's ever worked as a croupier how often '7' comes up when rolling 2*6-sided die )

Thanks will try the function as it could be used across the board,only just started reading up on functions and prototypes but will give it a go

Originally Posted by Bench82

Actually, maybe a little too random - extreme' values would be more common, and the 'middle-road' values would occur less frequendly.. The distribution should be uneven (in theory) so that rolls with multiple die are typically biased towards the middle-road values.

The sum of multiple dice rolls is equivalent (well, only roughly) to drawing values from a Gaussian distribution. So you can do it with a single call to rand(), but the expression is a bit more complex.

Originally Posted by brewbuck

The sum of multiple dice rolls is equivalent (well, only roughly) to drawing values from a Gaussian distribution. So you can do it with a single call to rand(), but the expression is a bit more complex.

Yeah, one rand() call will give the wrong distribution - flat.

Try something like the above roll function, but I'd optimise all those +1's:

Code:

int roll(int sides, int num_dice)
{
    int sum = num_dice;
    for( int i = 0; i < num_dice; ++i)
        sum += rand() &#37; sides;

    return sum;
} 

/* ... */

int playerHealth = roll( 10, 5 );