inverse array

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

void inverse (int *arr, const size_t size)
{
    size_t i, j;
    int swap;
    for (i = 0, j = size - 1; i < size / 2; i++, j--)
    {
        swap = arr[i];
        arr[i] = arr[j];
        arr[j] = swap;
    }
}

int main (void)
{
    int *arr = NULL;
    int i, n;

    srand((unsigned)time(NULL));
    printf("Enter number of elements: ");
    scanf("%d", &n);
    arr = (int *)malloc(sizeof(int) * n);

    for (i = 0; i < n; i++)
        printf("%3d", (arr[i] = rand() % 100));

    printf("\nafter inversion\n");
    inverse(arr, n);

    for (i = 0; i < n; i++)
        printf("%3d", arr[i]);

    free(arr);
    system("pause > nul");
    return 0;
}