two quick questions

[tbwttihs]

firstly, im trying to generate 'random' numbers between zero and 49 (guess what for). currently im using:

time_t t;
srand(unsigned (time(&t)));
int num = (rand() % 49);

but as that stands, the numbers im getting dont seem very random. in fact they seem like theyre just being plucked from a sequential count through 0 - 49. also, its wasting a lot of time in my while loop becuase the same number will be generated lots of times before it changes. what more effective way is there of achieving this?

also, i have a simple array which im putting these numbers into "numbers[6]". for my 6 numbers. what sorta syntax would i need to use to sort it into ascending order using the qsort() function? or failing that, what other simple sort algorithms are there that could be used?

cheers,

craig.

 

[dileeprd]

answer to ur second question:

why not use a simple sorting alg like bubble sort or selection sort and get done with it, and ur array size seems to b really small and no optimization is needed.

 

[xwb]

The algo below is what I use for picking unique cards in the card games I used to write in Uni. Basically pick one and put the one at the end in its position.
You could use selection sort to sort the numbers.

#include <stdio.h>
#include <time.h>
#include <stdlib.h>

#define NOTPICKEDMAX 50
#define PICKEDMAX 6
int main(int argc, char* argv[])
{
    int notpicked[NOTPICKEDMAX], n, p, remain, picked[PICKEDMAX], temp;
    
    srand (time (0));
    
    // Set up a list of numbers we can pick
    for (n = 1; n < NOTPICKEDMAX; n++)
        notpicked[n] = n;
    
    remain = NOTPICKEDMAX;
    for (p = 0; p < PICKEDMAX; p++)
    {
        // Get a number
        remain--;
        n = rand () % remain + 1;
        picked[p] = notpicked[n];
        
        // Move the one that we did not choose to the vacant position
        notpicked[n] = notpicked[remain];
    }
    
    // Sort the numbers in order
    for (p = 0; p < PICKEDMAX - 1; p++)
    {
        for (n = p + 1; n < PICKEDMAX; n++)
        {
            if (picked[p] > picked[n])
            {
                temp = picked[n];
                picked[n] = picked[p];
                picked[p] = temp;
            }
        }
    }
    
    // Print it out
    for (p = 0; p < PICKEDMAX; p++) 
        printf ("%d ", picked[p]);
    printf ("\n");
    return 0;
}