Contoh membuat class Stack sendiri pada Java

Stack.java

public class Stack {
	
  public int[] data;
  public int top;
	
  public Stack(int n) {
    this.data = new int[n];
    this.top = 0;
  }
	
  public void push(int d) {
    if (this.top < this.data.length) {
      this.data[this.top] = d;
      this.top++;
    }
  }
	
  public int pop() {
    if (this.top > 0) {
      this.top--;
      return this.data[this.top];
    }
    return 0;
  }
	
  public int peek() {
    if (this.top > 0) {
      return this.data[this.top-1];
    }
    return 0;
  }
	
  public boolean empty() {
    return this.top == 0;
  }
}