Return inside loops in Java - Mini Project: Build & Apply

Return inside loops

📖 Scenario: Imagine you are checking a list of numbers to find if any number is even. Once you find the first even number, you want to stop checking and return that number immediately.

🎯 Goal: You will write a Java method that looks through an array of integers and returns the first even number it finds. If no even number is found, it returns -1.

📋 What You'll Learn

Create an integer array called numbers with the exact values: 3, 7, 10, 5, 8.

Create an integer variable called notFound and set it to -1.

Write a method called findFirstEven that takes an integer array parameter called nums and uses a for loop with variable i to check each number.

Inside the loop, use return to immediately return the first even number found.

If no even number is found after the loop, return the value of notFound.

In the main method, call findFirstEven(numbers) and print the returned value.

💡 Why This Matters

🌍 Real World

Finding the first item that meets a condition quickly is common in many programs, like searching for the first available seat or the first error in a list.

💼 Career

Understanding how to return early from loops helps write efficient code and is a common task in software development interviews and real projects.

1

Create the integer array

Create an integer array called numbers with these exact values: 3, 7, 10, 5, 8.

Java

# Create the integer array called numbers with values 3, 7, 10, 5, 8
// Your code here

Need a hint?

Use int[] numbers = {3, 7, 10, 5, 8}; to create the array.

2

Create the notFound variable

Create an integer variable called notFound and set it to -1.

Java

int[] numbers = {3, 7, 10, 5, 8};
// Create the integer variable notFound and set it to -1
// Your code here

Need a hint?

Write int notFound = -1; to create the variable.

3

Write the findFirstEven method

Write a method called findFirstEven that takes an integer array parameter called nums. Use a for loop with variable i to check each number. Inside the loop, use return to immediately return the first even number found. After the loop, return the value of notFound.

Java

int[] numbers = {3, 7, 10, 5, 8};
int notFound = -1;

// Write the findFirstEven method below
// Your code here

Need a hint?

Use a for loop and check if each number is even using nums[i] % 2 == 0. Return the number immediately if even.

4

Call the method and print the result

In the main method, call findFirstEven(numbers) and print the returned value using System.out.println.

Java

int[] numbers = {3, 7, 10, 5, 8};
int notFound = -1;

public static int findFirstEven(int[] nums) {
    int notFound = -1;
    for (int i = 0; i < nums.length; i++) {
        if (nums[i] % 2 == 0) {
            return nums[i];
        }
    }
    return notFound;
}

// Write the main method below
// Your code here

Need a hint?

Use System.out.println(findFirstEven(numbers)); inside main to print the first even number.