Java Program to Find Largest Number in an Array

Arrays are a core data structure in many programming languages, including Java. One common task you might encounter as a programmer is identifying the largest (or smallest) value within an array. In this article, we walk through creating a simple Java program to find the largest number in an array. 

The Strategy

• Assume the first element of the array is the largest. 
• Traverse through the array starting from the second element. 
• Compare every element with the current largest. 
• If you find an element larger than the current largest, update the largest. 

Java Program to Find Largest Number in an Array

public class LargestNumberFinder {

    public static void main(String[] args) {
        int[] arr = {25, 47, 33, 56, 19, 40};

        int largest = findLargest(arr);

        System.out.println("The largest number in the array is: " + largest);
    }

    public static int findLargest(int[] numbers) {
        int max = numbers[0];

        for (int i = 1; i < numbers.length; i++) {
            if (numbers[i] > max) {
                max = numbers[i];
            }
        }
        
        return max;
    }
}

Output:

The largest number in the array is: 56 

Step by Step Explanation: 

Setting Up the Array:

        int[] arr = {25, 47, 33, 56, 19, 40};

We've initialized an integer array arr containing 6 elements. Our task is to find the largest number in this collection. 

Initializing the Largest Number: 

        int max = numbers[0];

We start by assuming the first element of the array (numbers[0]) is the largest. 

Traversing and Comparing:

        for (int i = 1; i < numbers.length; i++) {
            if (numbers[i] > max) {
                max = numbers[i];
            }
        }

We then traverse through the array starting from the second element (at index 1). For each element, we compare it with our current largest (max). If the current element is larger, we update our max. 

Returning the Result:

        return max;

After traversing the entire array, we return the value of max, which now contains the largest number from the array.

Conclusion

Finding the largest number in an array is a fundamental problem that introduces beginners to the concept of traversal and comparison in arrays. This simple guide provides a step-by-step approach to achieve this using Java's foundational constructs. As you progress, you'll find more complex problems and data structures that build on these fundamental skills. Remember, every great programmer starts with mastering the basics. Keep practicing and happy coding!