Static Methods

Contoh Algoritma

• algorithm: Urutan instruksi program.

• Contoh: "Bake sugar cookies"

– Mix the dry ingredients.

– Cream the butter and sugar.

– Beat in the eggs.

– Stir in the dry ingredients.

– Set the oven temperature.

– Set the timer.

– Place the cookies into the oven.

– Allow the cookies to bake.

– Spread frosting and sprinkles onto the cookies.

Permasalahan

• Struktur tidak jelas: banyak instruksi yang sulit diingat.

• duplikasi:...

– Mix the dry ingredients.

– Cream the butter and sugar.

– Beat in the eggs.

– Stir in the dry ingredients.

– Set the oven temperature.

– Set the timer.

– Place the first batch of cookies into the oven.

– Allow the cookies to bake.

– Set the timer.

– Place the second batch of cookies into the oven.

– Allow the cookies to bake.

– Mix ingredients for frosting.

 Strukturisasi

• structured algorithm: Pisahkan menjadi instruksi terpisah.

1  Make the cookie batter.

– Mix the dry ingredients.

– Cream the butter and sugar.

– Beat in the eggs.

– Stir in the dry ingredients.

2  Bake the cookies.

– Set the oven temperature.

– Set the timer.

– Place the cookies into the oven.

– Allow the cookies to bake.

3  Add frosting and sprinkles.

– Mix the ingredients for the frosting.

– Spread frosting and sprinkles onto the cookies.

 Menghilangkan Duplikasi

• Suatu algoritma yang baik dapat menunjukkanprogram yang tidak terduplikasi.

–

1 Make the cookie batter.

– Mix the dry ingredients.

–...

–

2a Bake the cookies (first batch).

– Set the oven temperature.

– Set the timer.

–...

2b Bake the cookies (second batch).

–

3 Decorate the cookies.

–...

 Dengan Duplikasi

public class BakeCookies {

    public static void main(String[] args) {

        System.out.println("Mix the dry ingredients.");

        System.out.println("Cream the butter and sugar.");

        System.out.println("Beat in the eggs.");

        System.out.println("Stir in the dry ingredients.");

        System.out.println("Set the oven temperature.");

        System.out.println("Set the timer.");

        System.out.println("Place a batch of cookies into the oven.");

        System.out.println("Allow the cookies to bake.");

        System.out.println("Set the oven temperature.");

        System.out.println("Set the timer.");

        System.out.println("Place a batch of cookies into the oven.");

        System.out.println("Allow the cookies to bake.");

        System.out.println("Mix ingredients for frosting.");

        System.out.println("Spread frosting and sprinkles.");

    }

}

Static Methods

•static method: Suatu namagroup dari statement.

•Menunjukkan struktur program

•Menghilangkan duplikasi

–

–dekomposisi:
memecahkan menjadi methods

–

–

•Menuliskan static method seperti

menambahkaninstruksi baru.

Menggunakan Static Methods

1. Rancang Algoritma.

– Lihat dari struktur masalah, dan lihat duplikasi.

– Lihat tujuan dari solusi masalah.

2. Tuliskan method nya.

– Atur instruksi ke dalamgroup dan berikan namanya.

3. Jalankan.

– Dimulai dari main method.

 Perancangan Algoritma

// This program displays a delicious recipe for baking cookies.

public class BakeCookies2 {

    public static void main(String[] args) {

        // Step 1: Make the cake batter.

        System.out.println("Mix the dry ingredients.");

        System.out.println("Cream the butter and sugar.");

        System.out.println("Beat in the eggs.");

        System.out.println("Stir in the dry ingredients.");

        // Step 2a: Bake cookies (first batch).

        System.out.println("Set the oven temperature.");

        System.out.println("Set the timer.");

        System.out.println("Place a batch of cookies into the oven.");

        System.out.println("Allow the cookies to bake.");

        // Step 2b: Bake cookies (second batch).

        System.out.println("Set the oven temperature.");

        System.out.println("Set the timer.");

        System.out.println("Place a batch of cookies into the oven.");

        System.out.println("Allow the cookies to bake.");

        // Step 3: Decorate the cookies.

        System.out.println("Mix ingredients for frosting.");

        System.out.println("Spread frosting and sprinkles.");

    }

}

Pendeklarasian Method

Berikan nama untuk setiap method

• Syntax:


public static void name() {
    statement;
    statement;
    ...
    statement;
}

• Contoh:

public static void printWarning() {
    System.out.println("This product causes cancer");
    System.out.println("in lab rats and humans.");
}

 Memanggil Method

Jalankan

• Syntax:

  name();

–

–Kita bisa memanggil method berkali-kali.

–

• Contoh:

  printWarning();

– Output:

  This product causes cancer

  in lab rats and humans.

 Program dengan static method

public class FreshPrince {

    public static void main(String[] args) {

        rap();                 // Calling (running) the rap method

        System.out.println();

        rap();                 // Calling the rap method again

    }

    // This method prints the lyrics to my favoritesong.

    public static void rap() {

        System.out.println("Now this is the story all about how");

        System.out.println("My life got flipped turned upside-down");

    }

}

Output:

Now this is the story all about how

My life got flipped turned upside-down

Now this is the story all about how

My life got flipped turned upside-down

Final Program

// This program displays a delicious recipe for baking cookies.

public class BakeCookies3 {

    public static void main(String[] args) {

        makeBatter();

        bake();       // 1st batch

        bake();       // 2nd batch

        decorate();

    }

    

    // Step 1: Make the cake batter.

    public static void makeBatter() {

        System.out.println("Mix the dry ingredients.");

        System.out.println("Cream the butter and sugar.");

        System.out.println("Beat in the eggs.");

        System.out.println("Stir in the dry ingredients.");

    }

    // Step 2: Bake a batch of cookies.

    public static void bake() {

        System.out.println("Set the oven temperature.");

        System.out.println("Set the timer.");

        System.out.println("Place a batch of cookies into the oven.");

        System.out.println("Allow the cookies to bake.");

    }

   

    // Step 3: Decorate the cookies.

    public static void decorate() {

        System.out.println("Mix ingredients for frosting.");

        System.out.println("Spread frosting and sprinkles.");

    }

}

Methods Memanggil Methods

public class MethodsExample {

    public static void main(String[] args) {

        message1();

        message2();

        System.out.println("Done with main.");

    }

    public static void message1() {

        System.out.println("This is message1.");

    }

    public static void message2() {

        System.out.println("This is message2.");

        message1();

        System.out.println("Done with message2.");

    }

}

• Output:

This is message1.

This is message2.

This is message1.

Done with message2.

Done with main.

Aliran Kontrol

• Saat suatu method dipanggil...

– “berpindah" ke method tersebut dan menjalankannya. lalu

– “kembali" ke poin sebelumnya

}


Kapan Menggunakan Methods

• Gunakan static method jika:

– statements berhubungan secara struktural, dan/atau

– Berulang-ulang dipanggil / terduplikasi.

• Jangan gunakan static methods jika:

– Hanya satu println

– Hanya baris kosong

         – Tidak ada perulangan atau duplikasi



Terima Kasih :)