Dynamic array with random numbers

Question

I create Array with size N in cycle "for" and fill up random numbers.I have startPoint which means first size of array. endPoint it's end size, but step is step of size :)

for(int n = startPoint; n <= endPoint; n += step)
{
    int * Array = malloc(sizeof(int)*n);//Create dynamic array wit size n

    generationNumber(Array,n);// Function which generate random numbers and write to array

    printArray(Array,n);//Here I print array to cmd

    Executing(Array,n);//Here I execute some action with array, it's not important  

    free(Array);
}

So my problem is in results: enter image description here

It's a function generationNumber:

void generationNumber(int * Array, int n)
{
     srand((unsigned)time(NULL));

     for(int i = 0; i < n; i++)
     {
        Array[i] = rand()%1000;
     }

}

Why numbers are repeated? I feel that just add numbers to array.

Call `srand()` once from `main()`. Don't call it every time you want a set of random values. Resolution of `time()` is pretty poor, so calling it twice within (say) several seconds will give the same results each time. — Peter, May 07 '18 at 14:11
`srand` should be called once at the beginning of your program. — Retired Ninja, May 07 '18 at 14:11

score 1 · Accepted Answer · answered May 07 '18 at 14:12

1

srand((unsigned)time(NULL)); will seed rand() with the current time in seconds. Running srand((unsigned)time(NULL)); more than once in a second will reset its state.

answered May 07 '18 at 14:12

N00byEdge

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Dynamic array with random numbers

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