java顺序栈功能通过数组实现

快来打我* 2023-10-11 10:47 77阅读 0赞

1.定义栈接口

1 public interface Stack<T> {
     2 //返回栈的大小
     3     public int size();
     4 //判断栈是否为空
     5     public boolean isEmpty();
     6 //入栈
     7     public void push(T t);
     8 //出栈
     9     public Object pop() throws StackEmptyException;
    10 //返回栈顶元素
    11     public Object peek() throws StackEmptyException ;
    12 }

2.自定义异常

1 public class StackEmptyException extends RuntimeException {
    2 //新增栈为空的异常类
    3     public StackEmptyException(String eMeaasge ){
    4         super(eMeaasge);
    5     }
    6 }

3.数组实现栈接口

1 public class StackArray<T> implements Stack<T> {
     2 //栈的初始容量为2；
     3     private final int LEN=2;
     4 //    定义栈的指针；
     5     private int top;
     6 //    栈以数组实现
     7     private T[] elements;
     8 //    构造方法进行初始化
     9     public StackArray(){
    10         top=-1;
    11         elements= (T[]) new Object[LEN];
    12     }
    13 
    14     @Override
    15     public int size() {
    16         return top+1;
    17     }
    18 
    19     @Override
    20     public boolean isEmpty() {
    21         return top<0;
    22     }
    23 
    24     @Override
    25     public void push(T t) {
    26         if(this.size()==elements.length){
    27          this.expandSize();
    28         }
    29 //        ++top，先自增，再赋值
    30          elements[++top]=t;
    31     }
    32 
    33     @Override
    34     public Object pop() throws StackEmptyException {
    35         if(this.isEmpty()){
    36             throw new StackEmptyException("当前栈为空，无法出栈");
    37         }
    38         Object obj = elements[top];
    39 //        top--，先赋值，再自减
    40         elements[top--]=null;
    41         return obj ;
    42     }
    43 
    44     @Override
    45     public Object peek() throws StackEmptyException {
    46         if(this.isEmpty()){
    47             throw new StackEmptyException("当前栈为空，无内容");
    48         }
    49         return elements[top];
    50     }
    51 //栈容量扩容
    52     public void expandSize(){
    53         T[] a= (T[]) new Object[elements.length *2];
    54         for(int i=0;i<elements.length;i++){
    55             a[i]=elements[i];
    56         }
    57         elements=a;
    58     }
    59 }

4.测试

1 public class Main {
     2 
     3     public static void main(String[] args) {
     4         StackArray<Integer> stackArray = new StackArray<Integer>();
     5         System.out.println(stackArray.size());
     6        /* stackArray.pop();*/
     7         stackArray.push(1);
     8         stackArray.push(2);
     9         stackArray.push(5);
    10         stackArray.push(6);
    11         System.out.println(stackArray.size());
    12         System.out.println(stackArray.peek());
    13 
    14 
    15     }
    16 }

5.测试结果

![1663737-20190914205711787-748488666.png][]

转载于:https://www.cnblogs.com/WhiperHong/p/11520210.html

[1663737-20190914205711787-748488666.png]: https://img2018.cnblogs.com/blog/1663737/201909/1663737-20190914205711787-748488666.png