Bash Average of Three Numbers using Arithmetic Expansion

In this tutorial, you will learn how to calculate the average of three numbers in Bash using arithmetic expansion. Arithmetic expansion is a simple and efficient way to perform calculations in Bash using the $(( expression )) syntax.

The formula for calculating the average of three numbers is:

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average = (num1 + num2 + num3) / 3

We will demonstrate how to calculate the average by summing the three numbers and then dividing the result by 3, all using arithmetic expansion.

Average of Three Numbers Bash Program

Steps:

  1. Define three numbers: Three variables, num1, num2, and num3, are initialized with the values 10, 15, and 20, respectively.
  2. Calculate the average: The average of the three numbers is calculated using arithmetic expansion in Bash. The expression ((num1 + num2 + num3) / 3) adds the three numbers together and divides the sum by 3 to compute the average. The result is assigned to the variable average.
  3. Output the result: The script uses the echo command to display the values of the three numbers and their calculated average on the console. Variable substitution ($num1, $num2, $num3, and $average) ensures the actual values are included in the output message.

Here’s a program that calculates the average of three numbers using arithmetic expansion.

Program

average_three.sh

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#!/bin/bash
# Define three numbers
num1=10
num2=15
num3=20

# Calculate the average using arithmetic expansion
average=$(( (num1 + num2 + num3) / 3 ))

# Output the result
echo "The average of $num1, $num2, and $num3 is $average"

Output

The average of 10, 15, and 20 is 15