Unary operators in Java - Mini Project: Build & Apply

Unary Operators in Java

📖 Scenario: You are working on a simple Java program that helps a cashier calculate the number of items left after selling some. You will use unary operators to increase or decrease the count.

🎯 Goal: Build a Java program that uses unary operators to update the count of items sold and items left.

📋 What You'll Learn

Create an integer variable for the initial number of items

Create an integer variable for the number of items sold

Use unary operators to increase and decrease counts

Print the final count of items left

💡 Why This Matters

🌍 Real World

Cashiers and inventory managers often need to update counts quickly when items are sold or restocked.

💼 Career

Understanding unary operators helps in writing concise code for counters, loops, and state changes in many software jobs.

1

Create initial item count

Create an integer variable called items and set it to 10.

Java

// Create an integer variable called items and set it to 10
// Your code here

Need a hint?

Use int to declare a whole number variable.

2

Create sold items count

Create an integer variable called sold and set it to 0.

Java

int items = 10;
// Create an integer variable called sold and set it to 0
// Your code here

Need a hint?

Initialize sold with zero because no items are sold yet.

3

Use unary operators to update sold count

Use the unary increment operator ++ to increase sold by 1.

Java

int items = 10;
int sold = 0;
// Increase sold by 1 using ++ operator
// Your code here

Need a hint?

The ++ operator adds one to the variable.

4

Calculate and print items left

Use the unary decrement operator -- to decrease items by 1, then print the value of items.

Java

int items = 10;
int sold = 0;
sold++;
// Decrease items by 1 using -- operator
// Print items
// Your code here

Need a hint?

The -- operator subtracts one from the variable. Use System.out.println(items); to print.