Java Program - Array Totals and Averages¶

Concept Explanation¶

What is it?¶

This program iterates through an array of numbers to calculate two key statistics: the total sum of all values and their average (mean).

Why is it important?¶

Aggregating data is a primary function of arrays. Whether processing student marks, daily sales figures, or temperature readings, calculating totals and averages is a standard requirement.

Algorithm¶

Start
Declare an array of integers (e.g., numbers).
Initialize sum = 0.
Loop through each element of the array.
Add the current element to sum.
Calculate average = sum / array_length.
Display sum and average.
End

Implementations¶

Java (JDK 17)

import java.util.Scanner;

public class ArrayStats {
    public static void main(String[] args) {
        // Sample Data
        int[] numbers = {10, 20, 30, 40, 50};

        int sum = 0;
        double average;

        // Calculate Sum
        for (int i = 0; i < numbers.length; i++) {
            sum += numbers[i];
        }

        // Calculate Average
        // Cast to double to preserve decimal precision
        average = (double) sum / numbers.length;

        System.out.println("Array Elements: ");
        for (int num : numbers) {
            System.out.print(num + " ");
        }
        System.out.println("\n-------------------");
        System.out.println("Total Sum: " + sum);
        System.out.println("Average:   " + average);
    }
}

Explanation¶

Java
Array Length: numbers.length gives the total count of elements.
Type Casting: (double) sum is crucial. Without it, integer division would occur (e.g., 150 / 5 = 30), potentially losing decimal values if the average wasn't a whole number.
Enhanced For Loop: Used for printing elements cleanly.

Complexity Analysis¶

Time Complexity: O(n) - We visit every element once.
Space Complexity: O(1) - We only use a few variables for tracking.

Practice Problems¶

Easy¶

Modify the program to accept 5 numbers from the user.

Medium¶

Find the maximum and minimum values in the same loop.

"Statistics are the grammar of science." - Karl Pearson