Contoh Program Array 2 Dimensi Java

Konsep Dasar Array 2 Dimensi

Sebelum masuk ke implementasi, penting untuk memahami konsep array dalam java secara menyeluruh. Array 2D dapat dibayangkan sebagai tabel dengan baris dan kolom.

Deklarasi dan Inisialisasi Array 2D

Ada beberapa cara untuk mendeklarasikan dan menginisialisasi array 2 dimensi dalam Java.

public class Array2DDeclaration {
    public static void main(String[] args) {
        
        // 1. Deklarasi dengan ukuran tetap
        int[][] matrix1 = new int[3][4]; // 3 baris, 4 kolom
        
        // 2. Deklarasi dengan inisialisasi langsung
        int[][] matrix2 = {
            {1, 2, 3, 4},
            {5, 6, 7, 8},
            {9, 10, 11, 12}
        };
        
        // 3. Deklarasi dengan inisialisasi bertahap
        int[][] matrix3 = new int[2][3];
        matrix3[0][0] = 10;
        matrix3[0][1] = 20;
        matrix3[0][2] = 30;
        matrix3[1][0] = 40;
        matrix3[1][1] = 50;
        matrix3[1][2] = 60;
        
        // 4. Jagged Array (array dengan panjang baris berbeda)
        int[][] jaggedArray = {
            {1, 2},
            {3, 4, 5, 6},
            {7, 8, 9}
        };
        
        // 5. Deklarasi dengan new operator
        int[][] matrix4 = new int[][] {
            {100, 200},
            {300, 400},
            {500, 600}
        };
        
        // Menampilkan matrix2
        System.out.println("Matrix 2 (3x4):");
        for (int i = 0; i < matrix2.length; i++) {
            for (int j = 0; j < matrix2[i].length; j++) {
                System.out.print(matrix2[i][j] + "\t");
            }
            System.out.println();
        }
        
        // Menampilkan jagged array
        System.out.println("\nJagged Array:");
        for (int i = 0; i < jaggedArray.length; i++) {
            for (int j = 0; j < jaggedArray[i].length; j++) {
                System.out.print(jaggedArray[i][j] + "\t");
            }
            System.out.println();
        }
    }
}

Contoh 1: Operasi Dasar Array 2D

Program ini mendemonstrasikan operasi-operasi dasar pada array 2D seperti input, output, dan manipulasi data. Pemahaman tentang perulangan for loop java sangat penting untuk bagian ini.

import java.util.Scanner;

public class Array2DBasicOperations {
    
    // Method untuk input array 2D dari user
    public static void inputArray(int[][] arr, Scanner scanner) {
        System.out.println("Masukkan elemen array:");
        for (int i = 0; i < arr.length; i++) {
            for (int j = 0; j < arr[i].length; j++) {
                System.out.print("Element [" + i + "][" + j + "]: ");
                arr[i][j] = scanner.nextInt();
            }
        }
    }
    
    // Method untuk menampilkan array 2D
    public static void displayArray(int[][] arr, String title) {
        System.out.println("\n" + title + ":");
        System.out.println("+" + "-".repeat(arr[0].length * 8) + "+");
        
        for (int i = 0; i < arr.length; i++) {
            System.out.print("|");
            for (int j = 0; j < arr[i].length; j++) {
                System.out.printf("%6d  ", arr[i][j]);
            }
            System.out.println("|");
        }
        System.out.println("+" + "-".repeat(arr[0].length * 8) + "+");
    }
    
    // Method untuk mencari nilai maksimum
    public static int findMax(int[][] arr) {
        int max = arr[0][0];
        for (int i = 0; i < arr.length; i++) {
            for (int j = 0; j < arr[i].length; j++) { if (arr[i][j] > max) {
                    max = arr[i][j];
                }
            }
        }
        return max;
    }
    
    // Method untuk mencari nilai minimum
    public static int findMin(int[][] arr) {
        int min = arr[0][0];
        for (int i = 0; i < arr.length; i++) {
            for (int j = 0; j < arr[i].length; j++) {
                if (arr[i][j] < min) {
                    min = arr[i][j];
                }
            }
        }
        return min;
    }
    
    // Method untuk menghitung sum semua elemen
    public static int calculateSum(int[][] arr) {
        int sum = 0;
        for (int i = 0; i < arr.length; i++) {
            for (int j = 0; j < arr[i].length; j++) {
                sum += arr[i][j];
            }
        }
        return sum;
    }
    
    // Method untuk menghitung rata-rata
    public static double calculateAverage(int[][] arr) {
        int sum = calculateSum(arr);
        int totalElements = arr.length * arr[0].length;
        return (double) sum / totalElements;
    }
    
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        
        System.out.println("=== PROGRAM OPERASI ARRAY 2D ===");
        
        // Input ukuran array
        System.out.print("Masukkan jumlah baris: ");
        int rows = scanner.nextInt();
        System.out.print("Masukkan jumlah kolom: ");
        int cols = scanner.nextInt();
        
        // Buat array 2D
        int[][] matrix = new int[rows][cols];
        
        // Input data
        inputArray(matrix, scanner);
        
        // Tampilkan array
        displayArray(matrix, "Array 2D yang diinput");
        
        // Hitung dan tampilkan statistik
        System.out.println("\n=== STATISTIK ARRAY ===");
        System.out.println("Nilai Maksimum: " + findMax(matrix));
        System.out.println("Nilai Minimum: " + findMin(matrix));
        System.out.println("Jumlah semua elemen: " + calculateSum(matrix));
        System.out.printf("Rata-rata: %.2f%n", calculateAverage(matrix));
        
        scanner.close();
    }
}

Contoh 2: Operasi Matrix Matematika

Program ini mengimplementasikan operasi matematika dasar pada matrix seperti penjumlahan, pengurangan, dan perkalian.

public class MatrixOperations {
    
    // Method untuk penjumlahan matrix
    public static int[][] addMatrix(int[][] matrix1, int[][] matrix2) {
        int rows = matrix1.length;
        int cols = matrix1[0].length;
        int[][] result = new int[rows][cols];
        
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < cols; j++) {
                result[i][j] = matrix1[i][j] + matrix2[i][j];
            }
        }
        return result;
    }
    
    // Method untuk pengurangan matrix
    public static int[][] subtractMatrix(int[][] matrix1, int[][] matrix2) {
        int rows = matrix1.length;
        int cols = matrix1[0].length;
        int[][] result = new int[rows][cols];
        
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < cols; j++) {
                result[i][j] = matrix1[i][j] - matrix2[i][j];
            }
        }
        return result;
    }
    
    // Method untuk perkalian matrix
    public static int[][] multiplyMatrix(int[][] matrix1, int[][] matrix2) {
        int rows1 = matrix1.length;
        int cols1 = matrix1[0].length;
        int cols2 = matrix2[0].length;
        
        int[][] result = new int[rows1][cols2];
        
        for (int i = 0; i < rows1; i++) {
            for (int j = 0; j < cols2; j++) {
                for (int k = 0; k < cols1; k++) {
                    result[i][j] += matrix1[i][k] * matrix2[k][j];
                }
            }
        }
        return result;
    }
    
    // Method untuk transpose matrix
    public static int[][] transposeMatrix(int[][] matrix) {
        int rows = matrix.length;
        int cols = matrix[0].length;
        int[][] result = new int[cols][rows];
        
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < cols; j++) {
                result[j][i] = matrix[i][j];
            }
        }
        return result;
    }
    
    // Method untuk menampilkan matrix dengan format rapi
    public static void printMatrix(int[][] matrix, String title) {
        System.out.println("\n" + title + ":");
        for (int i = 0; i < matrix.length; i++) {
            System.out.print("[ ");
            for (int j = 0; j < matrix[i].length; j++) {
                System.out.printf("%4d ", matrix[i][j]);
            }
            System.out.println("]");
        }
    }
    
    // Method untuk cek apakah matrix bisa dikalikan
    public static boolean canMultiply(int[][] matrix1, int[][] matrix2) {
        return matrix1[0].length == matrix2.length;
    }
    
    public static void main(String[] args) {
        System.out.println("=== OPERASI MATRIX MATEMATIKA ===");
        
        // Matrix A (3x3)
        int[][] matrixA = {
            {1, 2, 3},
            {4, 5, 6},
            {7, 8, 9}
        };
        
        // Matrix B (3x3)
        int[][] matrixB = {
            {9, 8, 7},
            {6, 5, 4},
            {3, 2, 1}
        };
        
        // Matrix C (3x2) untuk perkalian
        int[][] matrixC = {
            {1, 2},
            {3, 4},
            {5, 6}
        };
        
        // Tampilkan matrix awal
        printMatrix(matrixA, "Matrix A");
        printMatrix(matrixB, "Matrix B");
        printMatrix(matrixC, "Matrix C");
        
        // Operasi penjumlahan
        int[][] sum = addMatrix(matrixA, matrixB);
        printMatrix(sum, "A + B");
        
        // Operasi pengurangan
        int[][] difference = subtractMatrix(matrixA, matrixB);
        printMatrix(difference, "A - B");
        
        // Operasi perkalian
        if (canMultiply(matrixA, matrixC)) {
            int[][] product = multiplyMatrix(matrixA, matrixC);
            printMatrix(product, "A × C");
        } else {
            System.out.println("Matrix A dan C tidak bisa dikalikan!");
        }
        
        // Transpose matrix
        int[][] transposeA = transposeMatrix(matrixA);
        printMatrix(transposeA, "Transpose A");
        
        // Demonstrasi perkalian matrix persegi
        int[][] squareProduct = multiplyMatrix(matrixA, matrixB);
        printMatrix(squareProduct, "A × B");
    }
}

Contoh 3: Sistem Nilai Siswa

Program ini menggunakan array 2D untuk menyimpan dan mengolah data nilai siswa dalam berbagai mata pelajaran.

import java.util.Scanner;

public class StudentGradeSystem {
    
    private static String[] studentNames;
    private static String[] subjects;
    private static int[][] grades;
    
    // Method untuk input data siswa dan nilai
    public static void inputGrades(Scanner scanner) {
        System.out.print("Masukkan jumlah siswa: ");
        int numStudents = scanner.nextInt();
        System.out.print("Masukkan jumlah mata pelajaran: ");
        int numSubjects = scanner.nextInt();
        
        studentNames = new String[numStudents];
        subjects = new String[numSubjects];
        grades = new int[numStudents][numSubjects];
        
        scanner.nextLine(); // consume newline
        
        // Input nama siswa
        System.out.println("\n=== INPUT NAMA SISWA ===");
        for (int i = 0; i < numStudents; i++) {
            System.out.print("Nama siswa ke-" + (i + 1) + ": ");
            studentNames[i] = scanner.nextLine();
        }
        
        // Input nama mata pelajaran
        System.out.println("\n=== INPUT MATA PELAJARAN ===");
        for (int i = 0; i < numSubjects; i++) {
            System.out.print("Mata pelajaran ke-" + (i + 1) + ": ");
            subjects[i] = scanner.nextLine();
        }
        
        // Input nilai
        System.out.println("\n=== INPUT NILAI ===");
        for (int i = 0; i < numStudents; i++) {
            System.out.println("Nilai untuk " + studentNames[i] + ":");
            for (int j = 0; j < numSubjects; j++) {
                do {
                    System.out.print("  " + subjects[j] + " (0-100): ");
                    grades[i][j] = scanner.nextInt();
                    if (grades[i][j] < 0 || grades[i][j] > 100) {
                        System.out.println("  Nilai harus antara 0-100!");
                    }
                } while (grades[i][j] < 0 || grades[i][j] > 100);
            }
        }
    }
    
    // Method untuk menampilkan tabel nilai
    public static void displayGradeTable() {
        System.out.println("\n" + "=".repeat(80));
        System.out.println("                        TABEL NILAI SISWA");
        System.out.println("=".repeat(80));
        
        // Header tabel
        System.out.printf("%-20s", "NAMA SISWA");
        for (String subject : subjects) {
            System.out.printf("%-12s", subject.toUpperCase());
        }
        System.out.printf("%-10s%-8s%n", "RATA2", "GRADE");
        System.out.println("-".repeat(80));
        
        // Data siswa
        for (int i = 0; i < studentNames.length; i++) {
            System.out.printf("%-20s", studentNames[i]);
            
            int sum = 0;
            for (int j = 0; j < subjects.length; j++) { System.out.printf("%-12d", grades[i][j]); sum += grades[i][j]; } double average = (double) sum / subjects.length; String grade = getLetterGrade(average); System.out.printf("%-10.1f%-8s%n", average, grade); } System.out.println("=".repeat(80)); } // Method untuk konversi nilai ke huruf public static String getLetterGrade(double average) { if (average >= 90) return "A";
        else if (average >= 80) return "B";
        else if (average >= 70) return "C";
        else if (average >= 60) return "D";
        else return "E";
    }
    
    // Method untuk menghitung statistik per mata pelajaran
    public static void displaySubjectStatistics() {
        System.out.println("\n" + "=".repeat(60));
        System.out.println("              STATISTIK PER MATA PELAJARAN");
        System.out.println("=".repeat(60));
        System.out.printf("%-15s%-10s%-10s%-10s%-10s%n", 
                         "MATA PELAJARAN", "RATA2", "MAX", "MIN", "LULUS");
        System.out.println("-".repeat(60));
        
        for (int j = 0; j < subjects.length; j++) {
            int sum = 0, max = grades[0][j], min = grades[0][j], passed = 0;
            
            for (int i = 0; i < studentNames.length; i++) { sum += grades[i][j]; if (grades[i][j] > max) max = grades[i][j];
                if (grades[i][j] < min) min = grades[i][j]; if (grades[i][j] >= 70) passed++;
            }
            
            double average = (double) sum / studentNames.length;
            
            System.out.printf("%-15s%-10.1f%-10d%-10d%-10d%n", 
                             subjects[j], average, max, min, passed);
        }
        System.out.println("=".repeat(60));
    }
    
    // Method untuk mencari siswa terbaik
    public static void findTopStudent() {
        double maxAverage = 0;
        int topStudentIndex = 0;
        
        for (int i = 0; i < studentNames.length; i++) {
            int sum = 0;
            for (int j = 0; j < subjects.length; j++) { sum += grades[i][j]; } double average = (double) sum / subjects.length; if (average > maxAverage) {
                maxAverage = average;
                topStudentIndex = i;
            }
        }
        
        System.out.println("\n🏆 SISWA TERBAIK:");
        System.out.println("Nama: " + studentNames[topStudentIndex]);
        System.out.printf("Rata-rata: %.2f%n", maxAverage);
        System.out.println("Grade: " + getLetterGrade(maxAverage));
    }
    
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        
        System.out.println("=== SISTEM PENGELOLAAN NILAI SISWA ===");
        
        inputGrades(scanner);
        displayGradeTable();
        displaySubjectStatistics();
        findTopStudent();
        
        scanner.close();
    }
}

Contoh 4: Game Tic-Tac-Toe

Implementasi game Tic-Tac-Toe menggunakan array 2D untuk merepresentasikan papan permainan.

import java.util.Scanner;

public class TicTacToe {
    private static char[][] board = new char[3][3];
    private static char currentPlayer = 'X';
    
    // Method untuk inisialisasi papan
    public static void initializeBoard() {
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                board[i][j] = ' ';
            }
        }
    }
    
    // Method untuk menampilkan papan
    public static void displayBoard() {
        System.out.println("\n   0   1   2");
        for (int i = 0; i < 3; i++) {
            System.out.print(i + " ");
            for (int j = 0; j < 3; j++) {
                System.out.print(" " + board[i][j] + " ");
                if (j < 2) System.out.print("|");
            }
            System.out.println();
            if (i < 2) System.out.println(" -----------"); } System.out.println(); } // Method untuk cek apakah posisi valid public static boolean isValidMove(int row, int col) { return row >= 0 && row < 3 && col >= 0 && col < 3 && board[row][col] == ' ';
    }
    
    // Method untuk melakukan move
    public static void makeMove(int row, int col) {
        board[row][col] = currentPlayer;
    }
    
    // Method untuk cek pemenang
    public static boolean checkWinner() {
        // Cek baris
        for (int i = 0; i < 3; i++) {
            if (board[i][0] == currentPlayer && 
                board[i][1] == currentPlayer && 
                board[i][2] == currentPlayer) {
                return true;
            }
        }
        
        // Cek kolom
        for (int j = 0; j < 3; j++) {
            if (board[0][j] == currentPlayer && 
                board[1][j] == currentPlayer && 
                board[2][j] == currentPlayer) {
                return true;
            }
        }
        
        // Cek diagonal
        if (board[0][0] == currentPlayer && 
            board[1][1] == currentPlayer && 
            board[2][2] == currentPlayer) {
            return true;
        }
        
        if (board[0][2] == currentPlayer && 
            board[1][1] == currentPlayer && 
            board[2][0] == currentPlayer) {
            return true;
        }
        
        return false;
    }
    
    // Method untuk cek apakah papan penuh (draw)
    public static boolean isBoardFull() {
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (board[i][j] == ' ') {
                    return false;
                }
            }
        }
        return true;
    }
    
    // Method untuk ganti pemain
    public static void switchPlayer() {
        currentPlayer = (currentPlayer == 'X') ? 'O' : 'X';
    }
    
    // Method untuk menampilkan statistik game
    public static void displayGameStats() {
        int xCount = 0, oCount = 0, emptyCount = 0;
        
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (board[i][j] == 'X') xCount++;
                else if (board[i][j] == 'O') oCount++;
                else emptyCount++;
            }
        }
        
        System.out.println("=== STATISTIK GAME ===");
        System.out.println("X: " + xCount + " moves");
        System.out.println("O: " + oCount + " moves");
        System.out.println("Empty: " + emptyCount + " cells");
    }
    
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        
        System.out.println("=== WELCOME TO TIC-TAC-TOE ===");
        System.out.println("Player X starts first!");
        System.out.println("Enter row and column (0-2) to make a move.");
        
        initializeBoard();
        
        while (true) {
            displayBoard();
            System.out.println("Player " + currentPlayer + "'s turn");
            
            int row, col;
            
            // Input dengan validasi
            do {
                System.out.print("Enter row (0-2): ");
                row = scanner.nextInt();
                System.out.print("Enter column (0-2): ");
                col = scanner.nextInt();
                
                if (!isValidMove(row, col)) {
                    System.out.println("Invalid move! Try again.");
                }
            } while (!isValidMove(row, col));
            
            // Lakukan move
            makeMove(row, col);
            
            // Cek pemenang
            if (checkWinner()) {
                displayBoard();
                System.out.println("🎉 Player " + currentPlayer + " wins!");
                displayGameStats();
                break;
            }
            
            // Cek draw
            if (isBoardFull()) {
                displayBoard();
                System.out.println("🤝 It's a draw!");
                displayGameStats();
                break;
            }
            
            // Ganti pemain
            switchPlayer();
        }
        
        scanner.close();
    }
}

Contoh 5: Simulasi Image Processing

Program ini mensimulasikan operasi dasar image processing menggunakan array 2D untuk merepresentasikan pixel.

import java.util.Random;

public class ImageProcessingSimulation {
    
    // Method untuk generate random image (grayscale 0-255)
    public static int[][] generateRandomImage(int width, int height) {
        Random random = new Random();
        int[][] image = new int[height][width];
        
        for (int i = 0; i < height; i++) {
            for (int j = 0; j < width; j++) {
                image[i][j] = random.nextInt(256); // 0-255
            }
        }
        return image;
    }
    
    // Method untuk menampilkan image sebagai ASCII art
    public static void displayImage(int[][] image, String title) {
        System.out.println("\n" + title + ":");
        System.out.println("+" + "-".repeat(image[0].length * 2) + "+");
        
        for (int i = 0; i < image.length; i++) {
            System.out.print("|");
            for (int j = 0; j < image[i].length; j++) {
                // Convert grayscale to ASCII character
                char pixel = getASCIIChar(image[i][j]);
                System.out.print(pixel + " ");
            }
            System.out.println("|");
        }
        System.out.println("+" + "-".repeat(image[0].length * 2) + "+");
    }
    
    // Method untuk konversi nilai grayscale ke ASCII
    public static char getASCIIChar(int value) {
        if (value < 32) return '@';
        else if (value < 64) return '#';
        else if (value < 96) return '*';
        else if (value < 128) return '+';
        else if (value < 160) return '=';
        else if (value < 192) return '-';
        else if (value < 224) return '.';
        else return ' ';
    }
    
    // Method untuk brightness adjustment
    public static int[][] adjustBrightness(int[][] image, int adjustment) {
        int height = image.length;
        int width = image[0].length;
        int[][] result = new int[height][width];
        
        for (int i = 0; i < height; i++) {
            for (int j = 0; j < width; j++) {
                int newValue = image[i][j] + adjustment;
                // Clamp values between 0-255
                result[i][j] = Math.max(0, Math.min(255, newValue));
            }
        }
        return result;
    }
    
    // Method untuk contrast adjustment
    public static int[][] adjustContrast(int[][] image, double factor) {
        int height = image.length;
        int width = image[0].length;
        int[][] result = new int[height][width];
        
        for (int i = 0; i < height; i++) {
            for (int j = 0; j < width; j++) {
                int newValue = (int) ((image[i][j] - 128) * factor + 128);
                result[i][j] = Math.max(0, Math.min(255, newValue));
            }
        }
        return result;
    }
    
    // Method untuk blur effect (simple averaging)
    public static int[][] applyBlur(int[][] image) {
        int height = image.length;
        int width = image[0].length;
        int[][] result = new int[height][width];
        
        for (int i = 0; i < height; i++) {
            for (int j = 0; j < width; j++) {
                int sum = 0;
                int count = 0;
                
                // Check 3x3 neighborhood
                for (int di = -1; di <= 1; di++) {
                    for (int dj = -1; dj <= 1; dj++) { int ni = i + di; int nj = j + dj; if (ni >= 0 && ni < height && nj >= 0 && nj < width) {
                            sum += image[ni][nj];
                            count++;
                        }
                    }
                }
                
                result[i][j] = sum / count;
            }
        }
        return result;
    }
    
    // Method untuk edge detection (simple)
    public static int[][] detectEdges(int[][] image) {
        int height = image.length;
        int width = image[0].length;
        int[][] result = new int[height][width];
        
        for (int i = 1; i < height - 1; i++) {
            for (int j = 1; j < width - 1; j++) {
                // Sobel operator (simplified)
                int gx = -image[i-1][j-1] + image[i-1][j+1] +
                        -2*image[i][j-1] + 2*image[i][j+1] +
                        -image[i+1][j-1] + image[i+1][j+1];
                
                int gy = -image[i-1][j-1] - 2*image[i-1][j] - image[i-1][j+1] +
                         image[i+1][j-1] + 2*image[i+1][j] + image[i+1][j+1];
                
                int magnitude = (int) Math.sqrt(gx*gx + gy*gy);
                result[i][j] = Math.min(255, magnitude);
            }
        }
        return result;
    }
    
    // Method untuk histogram calculation
    public static void displayHistogram(int[][] image) {
        int[] histogram = new int[256];
        
        // Count pixel values
        for (int i = 0; i < image.length; i++) {
            for (int j = 0; j < image[i].length; j++) {
                histogram[image[i][j]]++;
            }
        }
        
        System.out.println("\n=== HISTOGRAM (simplified) ===");
        System.out.println("Range\tCount\tBar");
        System.out.println("-".repeat(30));
        
        // Group into ranges for display
        for (int range = 0; range < 8; range++) {
            int count = 0;
            int start = range * 32;
            int end = start + 31;
            
            for (int i = start; i <= end && i < 256; i++) {
                count += histogram[i];
            }
            
            System.out.printf("%d-%d\t%d\t", start, end, count);
            
            // Draw simple bar
            int barLength = count / 5; // Scale down
            for (int i = 0; i < barLength && i < 20; i++) {
                System.out.print("█");
            }
            System.out.println();
        }
    }
    
    public static void main(String[] args) {
        System.out.println("=== IMAGE PROCESSING SIMULATION ===");
        
        // Generate sample image
        int[][] originalImage = generateRandomImage(8, 6);
        
        // Display original
        displayImage(originalImage, "Original Image");
        displayHistogram(originalImage);
        
        // Brightness adjustment
        int[][] brighterImage = adjustBrightness(originalImage, 50);
        displayImage(brighterImage, "Brighter Image (+50)");
        
        // Contrast adjustment
        int[][] contrastImage = adjustContrast(originalImage, 1.5);
        displayImage(contrastImage, "Higher Contrast (1.5x)");
        
        // Blur effect
        int[][] blurredImage = applyBlur(originalImage);
        displayImage(blurredImage, "Blurred Image");
        
        // Edge detection
        int[][] edgeImage = detectEdges(originalImage);
        displayImage(edgeImage, "Edge Detection");
        
        System.out.println("\n=== PROCESSING COMPLETE ===");
        System.out.println("Image dimensions: " + originalImage[0].length + "x" + originalImage.length);
        System.out.println("Total pixels: " + (originalImage.length * originalImage[0].length));
    }
}

Contoh 6: Sistem Reservasi Tempat Duduk

Program ini mengimplementasikan sistem reservasi tempat duduk menggunakan array 2D untuk bioskop atau auditorium.

import java.util.Scanner;

public class SeatReservationSystem {
    private static char[][] seats;
    private static int rows, cols;
    private static int totalSeats, reservedSeats;
    
    // Method untuk inisialisasi sistem
    public static void initializeSeating(int numRows, int numCols) {
        rows = numRows;
        cols = numCols;
        seats = new char[rows][cols];
        totalSeats = rows * cols;
        reservedSeats = 0;
        
        // Initialize all seats as available ('O')
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < cols; j++) {
                seats[i][j] = 'O'; // O = Available
            }
        }
    }
    
    // Method untuk menampilkan layout tempat duduk
    public static void displaySeating() {
        System.out.println("\n" + "=".repeat(50));
        System.out.println("              LAYOUT TEMPAT DUDUK");
        System.out.println("=".repeat(50));
        System.out.println("Legend: O = Available, X = Reserved");
        System.out.println("-".repeat(50));
        
        // Header kolom
        System.out.print("   ");
        for (int j = 0; j < cols; j++) {
            System.out.printf("%3d", j + 1);
        }
        System.out.println();
        
        // Baris tempat duduk
        for (int i = 0; i < rows; i++) {
            System.out.printf("%2c ", 'A' + i); // Row labels A, B, C, etc.
            for (int j = 0; j < cols; j++) {
                System.out.printf(" %c ", seats[i][j]);
            }
            System.out.println();
        }
        
        System.out.println("-".repeat(50));
        System.out.println("Available: " + (totalSeats - reservedSeats) + 
                          " | Reserved: " + reservedSeats + 
                          " | Total: " + totalSeats);
        System.out.println("=".repeat(50));
    }
    
    // Method untuk reservasi tempat duduk
    public static boolean reserveSeat(int row, int col) {
        if (row < 0 || row >= rows || col < 0 || col >= cols) {
            System.out.println("❌ Invalid seat position!");
            return false;
        }
        
        if (seats[row][col] == 'X') {
            System.out.println("❌ Seat " + (char)('A' + row) + (col + 1) + 
                             " is already reserved!");
            return false;
        }
        
        seats[row][col] = 'X';
        reservedSeats++;
        System.out.println("✅ Seat " + (char)('A' + row) + (col + 1) + 
                          " reserved successfully!");
        return true;
    }
    
    // Method untuk cancel reservasi
    public static boolean cancelReservation(int row, int col) {
        if (row < 0 || row >= rows || col < 0 || col >= cols) {
            System.out.println("❌ Invalid seat position!");
            return false;
        }
        
        if (seats[row][col] == 'O') {
            System.out.println("❌ Seat " + (char)('A' + row) + (col + 1) + 
                             " is not reserved!");
            return false;
        }
        
        seats[row][col] = 'O';
        reservedSeats--;
        System.out.println("✅ Reservation for seat " + (char)('A' + row) + 
                          (col + 1) + " cancelled successfully!");
        return true;
    }
    
    // Method untuk mencari tempat duduk kosong berurutan
    public static void findConsecutiveSeats(int numSeats) {
        System.out.println("\n🔍 Searching for " + numSeats + 
                          " consecutive available seats...");
        
        boolean found = false;
        
        // Search row by row
        for (int i = 0; i < rows && !found; i++) {
            for (int j = 0; j <= cols - numSeats; j++) {
                boolean available = true;
                
                // Check if consecutive seats are available
                for (int k = 0; k < numSeats; k++) {
                    if (seats[i][j + k] == 'X') {
                        available = false;
                        break;
                    }
                }
                
                if (available) {
                    System.out.print("✅ Found consecutive seats: ");
                    for (int k = 0; k < numSeats; k++) {
                        System.out.print((char)('A' + i) + (j + k + 1));
                        if (k < numSeats - 1) System.out.print(", ");
                    }
                    System.out.println();
                    found = true;
                    break;
                }
            }
        }
        
        if (!found) {
            System.out.println("❌ No " + numSeats + 
                             " consecutive seats available.");
        }
    }
    
    // Method untuk statistik per baris
    public static void displayRowStatistics() {
        System.out.println("\n📊 STATISTIK PER BARIS:");
        System.out.println("-".repeat(40));
        System.out.printf("%-5s%-12s%-12s%-10s%n", 
                         "Row", "Available", "Reserved", "% Full");
        System.out.println("-".repeat(40));
        
        for (int i = 0; i < rows; i++) {
            int available = 0, reserved = 0;
            
            for (int j = 0; j < cols; j++) {
                if (seats[i][j] == 'O') available++;
                else reserved++;
            }
            
            double percentage = (double) reserved / cols * 100;
            
            System.out.printf("%-5c%-12d%-12d%-10.1f%%%n", 
                             'A' + i, available, reserved, percentage);
        }
        System.out.println("-".repeat(40));
    }
    
    // Method untuk auto-reserve best seats
    public static void autoReserveBestSeats(int numSeats) {
        System.out.println("\n🎯 Auto-reserving " + numSeats + " best seats...");
        
        // Priority: middle rows, middle columns
        int centerRow = rows / 2;
        int centerCol = cols / 2;
        
        int reserved = 0;
        
        // Try to reserve seats near center
        for (int distance = 0; distance < Math.max(rows, cols) && reserved < numSeats; distance++) {
            for (int i = Math.max(0, centerRow - distance); 
                 i <= Math.min(rows - 1, centerRow + distance) && reserved < numSeats; i++) {
                for (int j = Math.max(0, centerCol - distance); 
                     j <= Math.min(cols - 1, centerCol + distance) && reserved < numSeats; j++) {
                    
                    if (seats[i][j] == 'O') {
                        seats[i][j] = 'X';
                        reservedSeats++;
                        reserved++;
                        System.out.println("✅ Auto-reserved seat: " + 
                                         (char)('A' + i) + (j + 1));
                    }
                }
            }
        }
        
        if (reserved < numSeats) {
            System.out.println("⚠️  Only " + reserved + " seats could be reserved.");
        }
    }
    
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        
        System.out.println("=== SISTEM RESERVASI TEMPAT DUDUK ===");
        
        // Setup seating
        System.out.print("Masukkan jumlah baris: ");
        int numRows = scanner.nextInt();
        System.out.print("Masukkan jumlah kolom: ");
        int numCols = scanner.nextInt();
        
        initializeSeating(numRows, numCols);
        
        int choice;
        do {
            System.out.println("\n=== MENU ===");
            System.out.println("1. Tampilkan Layout");
            System.out.println("2. Reservasi Tempat Duduk");
            System.out.println("3. Cancel Reservasi");
            System.out.println("4. Cari Tempat Duduk Berurutan");
            System.out.println("5. Auto-Reserve Best Seats");
            System.out.println("6. Statistik Per Baris");
            System.out.println("0. Keluar");
            System.out.print("Pilih menu: ");
            choice = scanner.nextInt();
            
            switch (choice) {
                case 1:
                    displaySeating();
                    break;
                    
                case 2:
                    displaySeating();
                    System.out.print("Masukkan baris (A, B, C, ...): ");
                    char rowChar = scanner.next().toUpperCase().charAt(0);
                    System.out.print("Masukkan kolom (1, 2, 3, ...): ");
                    int colNum = scanner.nextInt();
                    
                    int rowIndex = rowChar - 'A';
                    int colIndex = colNum - 1;
                    
                    reserveSeat(rowIndex, colIndex);
                    break;
                    
                case 3:
                    displaySeating();
                    System.out.print("Masukkan baris untuk cancel (A, B, C, ...): ");
                    rowChar = scanner.next().toUpperCase().charAt(0);
                    System.out.print("Masukkan kolom untuk cancel (1, 2, 3, ...): ");
                    colNum = scanner.nextInt();
                    
                    rowIndex = rowChar - 'A';
                    colIndex = colNum - 1;
                    
                    cancelReservation(rowIndex, colIndex);
                    break;
                    
                case 4:
                    System.out.print("Berapa tempat duduk berurutan yang dicari? ");
                    int consecutive = scanner.nextInt();
                    findConsecutiveSeats(consecutive);
                    break;
                    
                case 5:
                    System.out.print("Berapa tempat duduk yang ingin di-reserve otomatis? ");
                    int autoReserve = scanner.nextInt();
                    autoReserveBestSeats(autoReserve);
                    break;
                    
                case 6:
                    displayRowStatistics();
                    break;
                    
                case 0:
                    System.out.println("Terima kasih telah menggunakan sistem reservasi!");
                    break;
                    
                default:
                    System.out.println("Pilihan tidak valid!");
            }
            
        } while (choice != 0);
        
        scanner.close();
    }
}

Analisis Performa dan Memory

Best Practices Array 2D Java

Common Pitfalls dan Solusinya