学习栈结构

刺骨的言语ヽ痛彻心扉 2022-07-18 16:28 62阅读 0赞

package com.loong.datastructure;
    
    /** * 学习栈结构 * * @author Loong * */
    public class Stack { 
        private Object[] stack = new Object[100];
        private int top = -1;
    
        /** * 获取栈顶元素 * * @return */
        public Object getTop() {
            if (stack == null) {
                throw new RuntimeException("栈未初始化");
            }
            if (isStackEmpty()) {
                throw new RuntimeException("栈已空");
            }
            return stack[top];
        }
    
        /** * 压栈 * * @param o */
        public void push(Object o) {
            if (stack == null) {
                throw new RuntimeException("栈未初始化");
            }
            if (isStackFull()) {
                throw new RuntimeException("栈向上溢出");
            }
            stack[++top] = o;
        }
    
        /** * 退栈 * * @return */
        public Object pop() {
            if (stack == null) {
                throw new RuntimeException("栈未初始化");
            }
            if (isStackEmpty()) {
                throw new RuntimeException("栈向下溢出");
            }
            return stack[top--];
        }
    
        /** * 判断栈是否已满 * * @return */
        public boolean isStackFull() {
            if (stack == null) {
                throw new RuntimeException("栈未初始化");
            }
            return stack.length - 1 == top;
        }
    
        /** * 判断栈是否为空 * * @return */
        public boolean isStackEmpty() {
            if (stack == null) {
                throw new RuntimeException("栈未初始化");
            }
            return top == -1;
        }
    
        /** * 初始化栈 * * @return */
        public int initStack() {
            return top = -1;
        }
    
    }