Perulangan while

Java Menengah

Jim White

Java Developer

Cara kerja while

Pertama, periksa kondisi
- Jika benar, jalankan kodenya
- Jika tidak, perulangan berhenti
Ulangi: periksa kondisi lalu putuskan

Skema perulangan while

Sintaks while

while (condition) {

  // Run this code

}

Sintaks mirip dengan pernyataan if
Berbeda dari if, dapat berjalan berulang kali

Contoh while

// Prints numbers smaller than 5
int counter = 1;

while (counter < 5){
  System.out.println(counter);
  counter = counter + 1;
}

Perulangan while tak berujung

Lupa memperbarui variabel

int counter = 1;

while (counter < 5){
  System.out.println(counter);
  counter = counter + 0;
}

➡ Menyebabkan program macet

Kondisi selalu true

int counter = 1;

while (counter < 5){
  System.out.println(counter);
  counter = counter - 1;
}

Operator pembaruan

int counter = 0;

// Same as counter = counter + 3
counter += 3;

Mirip dengan -=, *=, /=, ...

Break

Kita dapat memakai break untuk keluar dari while lebih awal, namun ini bukan praktik terbaik

int counter = 1;
while (counter < 5){
    System.out.println("Counter: " + counter);
    if (counter == 3) {
        break; // Exit the loop when counter is 3
    }
    counter+=2;
}

Counter: 1
Counter: 3

Ringkasan

// while loop that prints even numbers smaller than 20
int counter = 2;

while (counter < 20){
  System.out.println(counter);
  counter *= 2;

  // Exit while loop if counter is odd
  if (counter % 2 == 1){ // counter % 2 is counter modulo 2
    System.out.println("Something went wrong, counter is odd.");
    break;
  }
}

Ayo berlatih!

Java Menengah