Lucy's Note of Coding

public class Test {

  public static void main(String[] args) {
    ArrayStack stack = new ArrayStack(4);

    System.out.println("輸入show，顯示棧中所有值");
    System.out.println("輸入push，將值加入棧頂");
    System.out.println("輸入pop，從棧頂取出值");
    System.out.println("輸入exit，退出程式");
    System.out.println("請輸入一個指令~~");
    Scanner scanner = new Scanner(System.in);
    boolean shouldStop = false;

    while(scanner.hasNext()) {
      switch (scanner.next()) {
        case "show":
          stack.loopStack();
          break;
        case "push":
          System.out.println("請輸入要入棧的值：");
          stack.push(scanner.nextInt());
          break;
        case "pop":
          try {
            int popVal = stack.pop();
            System.out.printf("出棧的值：%d\n", popVal);
          } catch (Exception e) {
            System.out.println(e.getMessage());
          }
          break;
        case "exit":
          scanner.close();
          shouldStop = true;
          break;
      }
      if(shouldStop) break;
    }
  }
}

// imitate stack by array
class ArrayStack {
  private int stackSize;
  private int[] stack;
  private int top;

  public ArrayStack(int stackSize) {
    this.stackSize = stackSize;
    this.stack = new int[stackSize];
    this.top = -1;
  }

  /**
   * check stack is empty?
   * @return
   */
  public boolean isEmpty() {
    return top == -1;
  }

  /**
   * check stack is full?
   * @return
   */
  public boolean isFull() {
    return top == stackSize - 1;
  }

  /**
   * push value to the top of stack
   * @param value
   */
  public void push(int value) {
    if (isFull()) {
      System.out.println("棧滿~~");
      return;
    }
    top++;
    stack[top] = value;
  }

  /**
   * get out the top of stack value
   * @return
   */
  public int pop() {
    if (isEmpty()) {
      throw new RuntimeException("棧空，沒有資料");
    }
    int value = stack[top];
    top--;
    return value;
  }

  /**
   * loop stack from the top
   */
  public void loopStack() {
    if (isEmpty()) {
      System.out.println("棧空，沒有資料");
      return;
    }
    for (int i = top; i >= 0; i--) {
      System.out.printf("stack[%d]=%d\n", i, stack[i]);
    }
  }
}

如有敘述錯誤，還請不吝嗇留言指教，thanks!