public void occurrences(int [] a){
        quikSort(a);
        int count = 0;
        int temp = a[0];
        for (int i = 1 ; i < a.length ; i++){
            if (a[i] == temp )
                count++;
            else{
                System.out.println(temp + ":" + count + ",");
                temp = a[i];
                count = 1;
            }
        }
    }