// 1
public static String reverseString(String s) {
    String reverse = "";
    for(int i = s.length() - 1; i >= 0; i--)
        {
            reverse = reverse + s.charAt(i);
        }
    return reverse;
}

// 2
public static int sumDigits(long n){
    int temp = (int)Math.abs(n);
    int sum = 0;

    while(temp != 0){
        sum += (temp % 10);
        temp = temp / 10;
    }

    return sum;
}

// 3
public static void runningSum(int[] arr) {
    for(int i=1;i<arr.length;i++) {
       arr[i]=arr[i-1]+arr[i];
    }
}

// 4
public static int indexOfSmallest(int[] array){
    int value = 9999999;
    int index = 0;
    if(array.length > 0){
        for(int i = 0; i < array.length; i++){
            if(array[i] < value){
                value = array[i];
                index = i;
            }
        }
        return index;

    }
        else{
            return -1;
    }
}

// 5
public static int countLarger(int [] array, int num){
    int count = 0;
    for(int i = 0; i < array.length; i++){
        if(array[i] > num){
            count++;
        }

    }
    return count;

}

// 6
public static double average(double ... a){
    double ave = 0;
    double length = 0;
    for (double i : a){
        ave = ave + i;
        length++;
    }
    return ave/length;

}