void countSort(char arr[])
{

    char output[strlen(arr)];

    int count[RANGE +1], i;
    memset(count,0, sizeof(count));


    for(i = 0; arr[i]; ++i)
        ++count[arr[i]];

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


    for(i=0;arr[i];++i)
    {
        output[count[arr[i]]-1] = arr[i];
        --count[arr[i]];
    }
    for (i=0; arr[i]; ++i)
            arr[i] = output[i];
}