Radix sort (Implementation in C)

radixsort.c

#include <stdio.h>
#define RANGE 9

int getMax(int arr[], int n){
    int max = arr[0];

    for(int i = 1; i < n; i++){
        if(arr[i] > max){
            max = arr[i];
        }
    }

    return max;
}

void countsort(int arr[], int n, int d){
    int count[RANGE+1] = {0};
    int output[n];

    for(int i = 0; i < n; i++){
        count[(arr[i]/d)%10] += 1;
    }

    for(int i = 1; i <= RANGE; i++){
        count[i] += count[i-1];
    }

    for(int i = n-1; i >= 0; i--){
        output[count[(arr[i]/d)%10] - 1] = arr[i];
        count[(arr[i]/d)%10] -= 1;
    }

    for(int i = 0; i < n; i++){
        arr[i] = output[i];
    }
}

void radixsort(int arr[], int n){
    int max = getMax(arr, n);

    for(int d = 1; max/d > 0; d *= 10){
        countsort(arr, n, d);
    }
}

int main(){
    int arr[] = {170, 45, 75, 90, 802, 24, 2, 66};
    int n = sizeof(arr)/sizeof(arr[0]);
    radixsort(arr, n);
    printf("After sorting\n");
    for(int i = 0; i < n; i++){
        printf("%d ", arr[i]);
    }
    printf("\n");
    return 0;
}