MODUL AJAR

public class CommandLineDemo {
    public static void main(String[] args) {
        System.out.println("Jumlah argument: " + args.length);
        
        if (args.length > 0) {
            System.out.println("Argument yang diberikan:");
            for (int i = 0; i < args.length; i++) {
                System.out.println("args[" + i + "] = " + args[i]);
            }
        } else {
            System.out.println("Tidak ada argument yang diberikan");
        }
    }
}

javac CommandLineDemo.java
java CommandLineDemo Hello World 123

public class SyntaxDemo {
    
    // Variable class (static)
    static int counter = 0;
    
    // Variable instance
    int instanceVar;
    
    // Constructor
    public SyntaxDemo(int value) {
        this.instanceVar = value;
        counter++;
    }
    
    // Method dengan parameter dan return value
    public int tambah(int a, int b) {
        int hasil = a + b;  // Variable lokal
        return hasil;
    }
    
    // Static method
    public static void tampilkanCounter() {
        System.out.println("Counter: " + counter);
    }
    
    public static void main(String[] args) {
        // Membuat object
        SyntaxDemo obj1 = new SyntaxDemo(100);
        SyntaxDemo obj2 = new SyntaxDemo(200);
        
        // Memanggil method
        int jumlah = obj1.tambah(50, 30);
        System.out.println("Hasil penjumlahan: " + jumlah);
        
        // Mengakses variable
        System.out.println("Instance var obj1: " + obj1.instanceVar);
        System.out.println("Instance var obj2: " + obj2.instanceVar);
        
        // Memanggil static method
        tampilkanCounter();
        
        // Block scope demonstration
        int x = 10;
        {
            int y = 20;  // y hanya bisa diakses dalam blok ini
            System.out.println("x dalam blok: " + x);
            System.out.println("y dalam blok: " + y);
        }
        // System.out.println(y);  // ERROR! y tidak dikenal di sini
    }
}

public class OutputDemo {
    public static void main(String[] args) {
        // 1. println() - dengan baris baru
        System.out.println("Ini dengan println");
        System.out.println("Ini baris kedua");
        
        // 2. print() - tanpa baris baru
        System.out.print("Ini dengan print ");
        System.out.print("akan disambung");
        System.out.println(); // pindah baris
        
        // 3. printf() - format output
        String nama = "Budi";
        int umur = 20;
        double tinggi = 175.5;
        boolean aktif = true;
        
        System.out.printf("Nama: %s, Umur: %d tahun%n", nama, umur);
        System.out.printf("Tinggi: %.1f cm%n", tinggi);
        System.out.printf("Status aktif: %b%n", aktif);
        
        // 4. Format angka
        double harga = 1234567.89123;
        System.out.printf("Harga: Rp %,.2f%n", harga);
        
        // 5. Alignment
        System.out.printf("%-10s %10s %n", "Nama", "Nilai");
        System.out.printf("%-10s %10d %n", "Budi", 85);
        System.out.printf("%-10s %10d %n", "Ani", 92);
        System.out.printf("%-10s %10d %n", "Candra", 78);
        
        // 6. Output dengan escape sequences
        System.out.println("Baris 1\nBaris 2");  // newline
        System.out.println("Tab\tantara kata");    // tab
        System.out.println("Backslash: \\");        // backslash
        System.out.println("Petik satu: \'");       // single quote
        System.out.println("Petik dua: \"");        // double quote
        
        // 7. Output unicode
        System.out.println("Halo dalam berbagai bahasa:");
        System.out.println("Indonesia: Selamat datang");
        System.out.println("Jepang: こんにちは");
        System.out.println("China: 你好");
        System.out.println("Korea: 안녕하세요");
        
        // 8. Output dengan waktu
        System.out.printf("Tanggal: %tF%n", System.currentTimeMillis());
        System.out.printf("Waktu: %tT%n", System.currentTimeMillis());
    }
}

/**
 * Kelas Kalkulator untuk melakukan operasi matematika sederhana.
 * Kelas ini mendemonstrasikan penggunaan Javadoc comments.
 * 
 * @author Tim Pengembang
 * @version 1.0
 * @since 2024
 */
public class Kalkulator {
    
    /**
     * Konstanta untuk nilai PI
     */
    public static final double PI = 3.14159;
    
    /**
     * Menjumlahkan dua bilangan bulat.
     *
     * @param a bilangan pertama
     * @param b bilangan kedua
     * @return hasil penjumlahan a dan b
     */
    public int tambah(int a, int b) {
        // Variable lokal untuk menyimpan hasil
        int hasil = a + b;
        return hasil;
    }
    
    /**
     * Menghitung luas lingkaran.
     *
     * @param jariJari jari-jari lingkaran
     * @return luas lingkaran
     * @throws IllegalArgumentException jika jariJari <= 0
     */
    public double luasLingkaran(double jariJari) {
        /* Validasi input
           Memastikan jari-jari bernilai positif */
        if (jariJari <= 0) {
            throw new IllegalArgumentException("Jari-jari harus positif");
        }
        
        // Menghitung luas: π * r²
        return PI * jariJari * jariJari;
    }
    
    /**
     * Method utama untuk menjalankan program.
     *
     * @param args command line arguments
     */
    public static void main(String[] args) {
        // Membuat objek kalkulator
        Kalkulator calc = new Kalkulator();
        
        /* Demonstrasi penggunaan method
           Menampilkan hasil perhitungan */
        System.out.println("5 + 3 = " + calc.tambah(5, 3));
        System.out.println("Luas lingkaran r=7: " + calc.luasLingkaran(7));
    }
}

public class VariableDemo {
    
    // Instance variables
    String nama;
    int umur;
    double gaji;
    
    // Static/Class variables
    static String perusahaan = "PT Java Corp";
    static int jumlahKaryawan = 0;
    
    // Constructor
    public VariableDemo(String nama, int umur, double gaji) {
        this.nama = nama;
        this.umur = umur;
        this.gaji = gaji;
        jumlahKaryawan++;
    }
    
    // Method untuk menampilkan info
    public void tampilkanInfo() {
        // Local variables
        String jabatan = "Staf";
        double bonus = gaji * 0.1;
        double totalGaji = gaji + bonus;
        
        System.out.println("=== Data Karyawan ===");
        System.out.println("Nama: " + nama);
        System.out.println("Umur: " + umur + " tahun");
        System.out.println("Jabatan: " + jabatan);
        System.out.printf("Gaji Pokok: Rp %,.2f%n", gaji);
        System.out.printf("Bonus: Rp %,.2f%n", bonus);
        System.out.printf("Total Gaji: Rp %,.2f%n", totalGaji);
    }
    
    public static void main(String[] args) {
        // Local variables di main
        int tahunSekarang = 2024;
        
        // Membuat object
        VariableDemo karyawan1 = new VariableDemo("Budi Santoso", 30, 5000000);
        VariableDemo karyawan2 = new VariableDemo("Ani Wijaya", 28, 6000000);
        VariableDemo karyawan3 = new VariableDemo("Citra Dewi", 32, 7500000);
        
        // Memanggil method
        karyawan1.tampilkanInfo();
        System.out.println();
        karyawan2.tampilkanInfo();
        System.out.println();
        karyawan3.tampilkanInfo();
        
        // Mengakses static variable
        System.out.println("\n=== Informasi Perusahaan ===");
        System.out.println("Nama Perusahaan: " + perusahaan);
        System.out.println("Tahun: " + tahunSekarang);
        System.out.println("Jumlah Karyawan: " + jumlahKaryawan);
        
        // Demonstrasi final variable (konstanta)
        final double PAJAK = 0.1;
        System.out.println("Pajak: " + (PAJAK * 100) + "%");
        // PAJAK = 0.2;  // ERROR! tidak bisa mengubah final variable
        
        // Demonstrasi block scope
        {
            int x = 100;
            System.out.println("x dalam blok: " + x);
        }
        // System.out.println(x);  // ERROR! x tidak dikenal di sini
    }
}

public class DataTypesDemo {
    public static void main(String[] args) {
        System.out.println("=== Tipe Data Primitif ===\n");
        
        // 1. Integer types
        byte b = 127;
        short s = 32767;
        int i = 2147483647;
        long l = 9223372036854775807L;
        
        System.out.println("byte   : " + b + " (max: 127)");
        System.out.println("short  : " + s + " (max: 32767)");
        System.out.println("int    : " + i + " (max: 2.1M)");
        System.out.println("long   : " + l + " (max: 9.2E18)");
        
        // 2. Floating point types
        float f = 3.14159f;
        double d = 3.141592653589793;
        
        System.out.println("\nfloat  : " + f + " (presisi 6-7 digit)");
        System.out.println("double : " + d + " (presisi 15 digit)");
        
        // 3. Character type
        char c1 = 'A';
        char c2 = 65;  // ASCII value untuk 'A'
        char c3 = '\u0041';  // Unicode untuk 'A'
        
        System.out.println("\nchar   : " + c1);
        System.out.println("char(65): " + c2);
        System.out.println("char(\\u0041): " + c3);
        
        // 4. Boolean type
        boolean bool1 = true;
        boolean bool2 = false;
        boolean bool3 = (10 > 5);
        
        System.out.println("\nboolean: " + bool1);
        System.out.println("boolean: " + bool2);
        System.out.println("boolean(10>5): " + bool3);
        
        // 5. Reference types
        String str = "Hello Java";
        Integer num = 100;  // Wrapper class
        Double price = 99.99;  // Wrapper class
        Object obj = new Object();
        int[] arr = {1, 2, 3, 4, 5};
        
        System.out.println("\n=== Tipe Data Reference ===");
        System.out.println("String : " + str);
        System.out.println("Integer: " + num);
        System.out.println("Double : " + price);
        System.out.println("Array  : " + java.util.Arrays.toString(arr));
        
        // 6. Literals
        System.out.println("\n=== Literals ===");
        System.out.println("Binary 0b1010: " + 0b1010);  // Binary literal
        System.out.println("Octal 012: " + 012);        // Octal literal
        System.out.println("Hex 0xFF: " + 0xFF);         // Hex literal
        System.out.println("Underscore: " + 1_000_000);  // Underscore in numbers
        System.out.println("Scientific: " + 1.2e3);     // Scientific notation
        
        // 7. Type ranges
        System.out.println("\n=== Range Tipe Data ===");
        System.out.println("byte   : " + Byte.MIN_VALUE + " s/d " + Byte.MAX_VALUE);
        System.out.println("short  : " + Short.MIN_VALUE + " s/d " + Short.MAX_VALUE);
        System.out.println("int    : " + Integer.MIN_VALUE + " s/d " + Integer.MAX_VALUE);
        System.out.println("long   : " + Long.MIN_VALUE + " s/d " + Long.MAX_VALUE);
        System.out.println("float  : " + Float.MIN_VALUE + " s/d " + Float.MAX_VALUE);
        System.out.println("double : " + Double.MIN_VALUE + " s/d " + Double.MAX_VALUE);
    }
}

public class CastingDemo {
    public static void main(String[] args) {
        System.out.println("=== Widening Casting (Otomatis) ===\n");
        
        int intValue = 100;
        System.out.println("int value   : " + intValue);
        
        long longValue = intValue;  // Otomatis int -> long
        System.out.println("long value  : " + longValue);
        
        float floatValue = intValue;  // Otomatis int -> float
        System.out.println("float value : " + floatValue);
        
        double doubleValue = intValue;  // Otomatis int -> double
        System.out.println("double value: " + doubleValue);
        
        System.out.println("\n=== Narrowing Casting (Manual) ===\n");
        
        double d = 100.99;
        System.out.println("double value: " + d);
        
        float f = (float) d;  // Manual casting double -> float
        System.out.println("float value : " + f);
        
        long l = (long) d;    // Manual casting double -> long
        System.out.println("long value  : " + l);
        
        int i = (int) d;      // Manual casting double -> int
        System.out.println("int value   : " + i);
        
        short s = (short) i;  // Manual casting int -> short
        System.out.println("short value : " + s);
        
        byte b = (byte) i;    // Manual casting int -> byte
        System.out.println("byte value  : " + b);
        
        System.out.println("\n=== Casting dengan Overflow ===\n");
        
        int besar = 130;
        byte kecil = (byte) besar;  // Overflow karena byte max 127
        System.out.println("int 130  -> byte: " + kecil);  // -126 (overflow)
        
        double pi = 3.14159;
        int piInt = (int) pi;  // Truncation (pemotongan, bukan pembulatan)
        System.out.println("double 3.14159 -> int: " + piInt);
        
        System.out.println("\n=== Casting dengan Char ===\n");
        
        char ch = 'A';
        int charInt = (int) ch;  // char -> int (ASCII value)
        System.out.println("char 'A' -> int: " + charInt);  // 65
        
        int num = 66;
        char numChar = (char) num;  // int -> char
        System.out.println("int 66 -> char: '" + numChar + "'");  // 'B'
        
        System.out.println("\n=== Casting String ke Numerik ===\n");
        
        String strNumber = "123";
        int parsedInt = Integer.parseInt(strNumber);
        double parsedDouble = Double.parseDouble(strNumber);
        
        System.out.println("String '123' -> int: " + parsedInt);
        System.out.println("String '123' -> double: " + parsedDouble);
        
        // Konversi numerik ke String
        int angka = 456;
        String strAngka = Integer.toString(angka);
        String strAngka2 = String.valueOf(angka);
        
        System.out.println("int 456 -> String: '" + strAngka + "'");
        System.out.println("int 456 -> String: '" + strAngka2 + "'");
        
        System.out.println("\n=== Casting Object ===\n");
        
        Object obj = "Hello Java";
        String strObj = (String) obj;  // Downcasting object ke string
        System.out.println("Object -> String: " + strObj);
        
        // Instanceof untuk safety casting
        if (obj instanceof String) {
            String safeStr = (String) obj;
            System.out.println("Safe casting: " + safeStr);
        }
    }
}

public class OperatorsDemo {
    public static void main(String[] args) {
        int a = 10, b = 3;
        
        System.out.println("=== Operator Aritmatika ===");
        System.out.println("a = " + a + ", b = " + b);
        System.out.println("a + b = " + (a + b));
        System.out.println("a - b = " + (a - b));
        System.out.println("a * b = " + (a * b));
        System.out.println("a / b = " + (a / b));
        System.out.println("a % b = " + (a % b));
        
        System.out.println("\n=== Operator Penugasan ===");
        int x = 5;
        System.out.println("x = " + x);
        x += 3;  System.out.println("x += 3 -> " + x);
        x -= 2;  System.out.println("x -= 2 -> " + x);
        x *= 4;  System.out.println("x *= 4 -> " + x);
        x /= 2;  System.out.println("x /= 2 -> " + x);
        x %= 3;  System.out.println("x %= 3 -> " + x);
        
        System.out.println("\n=== Operator Increment/Decrement ===");
        int y = 5;
        System.out.println("y = " + y);
        System.out.println("y++ : " + y++ + " (post-increment)");
        System.out.println("sekarang y = " + y);
        System.out.println("++y : " + ++y + " (pre-increment)");
        System.out.println("sekarang y = " + y);
        
        System.out.println("\n=== Operator Perbandingan ===");
        System.out.println("a == b: " + (a == b));
        System.out.println("a != b: " + (a != b));
        System.out.println("a > b : " + (a > b));
        System.out.println("a < b : " + (a < b));
        System.out.println("a >= b: " + (a >= b));
        System.out.println("a <= b: " + (a <= b));
        
        System.out.println("\n=== Operator Logika ===");
        boolean p = true, q = false;
        System.out.println("p && q: " + (p && q));
        System.out.println("p || q: " + (p || q));
        System.out.println("!p    : " + (!p));
        
        System.out.println("\n=== Operator Ternary ===");
        int umur = 20;
        String status = (umur >= 17) ? "Dewasa" : "Anak-anak";
        System.out.println("Umur " + umur + " -> " + status);
        
        System.out.println("\n=== Operator Bitwise ===");
        int m = 6;  // 110 biner
        int n = 3;  // 011 biner
        System.out.println("m & n  : " + (m & n) + " (AND)");
        System.out.println("m | n  : " + (m | n) + " (OR)");
        System.out.println("m ^ n  : " + (m ^ n) + " (XOR)");
        System.out.println("~m     : " + (~m) + " (NOT)");
        System.out.println("m << 1 : " + (m << 1) + " (shift left)");
        System.out.println("m >> 1 : " + (m >> 1) + " (shift right)");
    }
}