Calculating Frequency of Integers.c

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

#define En(i)   (2*i)
#define On(i)   (2*i+1)

const int   none = -1;

typedef unsigned int    UINT;

UINT checkForVal(UINT* sort, UINT size, UINT num) {
    for (int i = 0; i < size; i += 2) {
        if (sort[i] == num)
            return i;
    }
    return none;
}

UINT init(int* arr) {
    UINT size, i, shift;
    srand((UINT)time(NULL));
    size = rand()%30+20;
    shift = rand() % 241;
    for (i = 0; i < size; i++) {
        arr[i] = (rand() % 15) + shift;
    }
    return size;
}

int main() {
    UINT arr[256] = { 0 }, aSize = 0;
    UINT sort[512] = { 0 }, sSize = 0;
    UINT holder = 0, frequency, tmp;
    aSize = init(arr);
    printf("Sample numbers: ");
    for (UINT i = 0; i < aSize; i++) {
        printf("%d, ", arr[i]);
    }

    for (UINT i = 0; i < aSize; i++, frequency = 0) {
        holder = arr[i];
        tmp = checkForVal(sort, sSize, holder);
        if (tmp == none) {
            sort[sSize] = holder;
            sort[sSize + 1]++;
            sSize += 2;
        }
        else {
            sort[tmp + 1]++;
        }
    }

    printf("\nFrequency:-");
    for (UINT i = 0; i < sSize; i += 2) {
        printf("\n%d - %d", sort[i], sort[i + 1]);
    }
    return 0;
}