Check if an Array is Sorted in Java (Ascending or Descending)

Checking if an array is sorted is a basic and commonly asked question in Java interviews. In this post, we’ll check if an array is sorted in ascending or descending order using simple logic.

🧠 Approach

We iterate through the array and compare each element with the next one:

• If all elements follow the order: arr[i] <= arr[i+1], then it's ascending.
• If all elements follow: arr[i] >= arr[i+1], then it's descending.
• Otherwise, it's unsorted.

✅ Java Program

public class CheckArraySorted {
    public static void main(String[] args) {
        int[] arr = {1, 3, 5, 7, 9};

        if (isSortedAscending(arr)) {
            System.out.println("Array is sorted in ascending order.");
        } else if (isSortedDescending(arr)) {
            System.out.println("Array is sorted in descending order.");
        } else {
            System.out.println("Array is not sorted.");
        }
    }

    static boolean isSortedAscending(int[] arr) {
        for (int i = 0; i < arr.length - 1; i++) {
            if (arr[i] > arr[i + 1]) {
                return false;
            }
        }
        return true;
    }

    static boolean isSortedDescending(int[] arr) {
        for (int i = 0; i < arr.length - 1; i++) {
            if (arr[i] < arr[i + 1]) {
                return false;
            }
        }
        return true;
    }
}

✅ Output

Array is sorted in ascending order.

💡 Tip

This program can be modified to work with float, double, or even String arrays using appropriate comparison logic.

📌 Conclusion

We learned how to check if an array is sorted in Java without using any built-in methods. This is useful in many scenarios like optimization, binary search, or validating input data.

✅ Master Array Traversal & Order Validation in Java

Checking whether an array is sorted is a foundational Java problem often used as a prerequisite for optimized algorithms. Strengthen your understanding of array traversal, comparisons, and edge cases by exploring these related Java programs and interview resources.

🧠 Java Coding Round Questions

Practice array-based logic problems asked in coding rounds.

🚫 Remove Duplicates from Array

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🔍 Find Duplicates in Array

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🔄 Reverse Array

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🥈 Second Largest Element in Array

Practice scanning arrays while maintaining value constraints.

📊 Sort Array Without Built-ins

Learn sorting algorithms often used before order validation.

📦 Java Collections Interview Questions

Understand ordering concepts in lists, sets, and maps.

🎯 Java Interview Questions (Freshers)

Common interview questions involving arrays and sorting.

🧪 Advanced Java Programs (Real-World)

Apply array-order validation in real-world Java problems.