Java Program to Calculate Sum and Average of 3 Numbers

Program Description:- Write a Java program to calculate the sum and average of 3 (three) numbers.

First, we will develop a simple Java program by hardcoding the values i.e. required values will be initialized inside the program.

Procedure to find the average of three numbers,
1) Take three numbers
2) Declare a sum variable
3) Calculate the addition of those three numbers and assign them to the sum variable
4) Find average as average = sum/3
5) Finally, display the result of the average value

Java Program to Calculate sum and average of 3 Numbers

public class Average {
  public static void main(String[] args) {

    // take two numbers
    double num1 = 10;
    double num2 = 15;
    double num3 = 20;

    // declare sum variable
    // and initialize with 0
    double sum = 0.0;
    // declare average variable
    double avg = 0.0;

    // calculate the sum value
    sum = num1 + num2 + num3;
    // calculate the average value
    avg = sum/3;

    // display result
    System.out.println("Average: " + avg );
  }
}

Output:-

Average: 15.0

In the above program, we have hardcoded the input values. Now, let us develop another Java program to do the same but take input value from the end-user.

Java Program to Calculate Sum and Average of 3 Numbers by taking input from end-user

import java.util.Scanner;
public class Average {
  public static void main(String[] args) {

    // create Scanner class object
    Scanner scan = new Scanner(System.in);

    // declare three numbers
    double num1 = 0;
    double num2 = 0;
    double num3 = 0;

    // declare sum variable
    // and initialize with 0
    double sum = 0.0;
    // declare average variable
    double avg = 0.0;

    // take three numbers
    System.out.print("Enter three numbers: ");
    num1 = scan.nextDouble();
    num2 = scan.nextDouble();
    num3 = scan.nextDouble();

    // calculate the sum value
    sum = num1 + num2 + num3;
    // calculate the average value
    avg = sum/3;

    // display result
    System.out.println("Average: " + avg );
  }
}

Output for the different test-cases:-

Enter three numbers: 15 25 35
Average: 25.0

Enter three numbers: 10 25 50
Average: 28.333333333333332

In the above program, first, we had declared all the variables. The num1, num2, and num3 variables will hold/store the input values. The sum variable is declared and initialized with 0, the average variable is also declared.

To take the input value from the end-user we have used the Scanner class which is defined in the java.util.Scanner package but you can also take any input-output stream class like BufferedReader class to read the input. The num1, num2, sum, and average variables are of double data type and can hold integer and floating-point values. See more about float and double data types in Java

Now, we had taken three numbers as input and calculated the sum value as sum = num1 + num2 + num3. Then we calculated the average value as avg = sum / 3. Finally, we got the average value and it is displayed on the screen.

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1 thought on “Java Program to Calculate Sum and Average of 3 Numbers”

  1. Good post however I was wanting to know if you could write a little more on this topic? I’d be very grateful if you could elaborate a little bit more. Many thanks!

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