栈的数组实现

来源：互联网发布：sql 排序后加上序号编辑：程序博客网时间：2024/06/05 00:49

今天复习下栈，自己写一遍：
1.栈是限制插入和删除只能在同一个位置上进行的表，该位置是表的末端叫做栈顶。栈有时也叫后进先出（LIFO）表，基本操作有pop（删除）和push（插入）。
2.栈的数组实现：

package com.algith;public class MyStack<T> {        private int size;        private T[] elements = null;        private static final int DEFAULT_SIZE = 10;        public MyStack(){                clear();        }        public int size(){                return size;        }        @SuppressWarnings("unchecked")        public void clear(){                size = 0;                elements = (T[]) new Object[DEFAULT_SIZE];        }        public void push(T t){                if(size==elements.length){                        ensureCapacity(size*2+1);                }                elements[size++] = t;        }        public T pop(){                if(size<1) return null;                int topIndex = size - 1;                T t = elements[topIndex];                remove(topIndex);                return t;        }        @SuppressWarnings("unchecked")        public void ensureCapacity(int capacity){                if(capacity<size)return;                T[] oldElements = elements;                elements = (T[]) new Object[capacity];                for(int i=0;i<size;i++){                        elements[i] = oldElements[i];                }        }        public T remove(int index){                if(index<0||index>size)                     throw new ArrayIndexOutOfBoundsException();                T removeValue = elements[index];                for(int i=index;i<size-1;i++){                        elements[i] = elements[i+1];                }                size--;                return removeValue;        }        public T get(int index){                if(index<0||index>size)                     throw new ArrayIndexOutOfBoundsException();                return elements[index];        }        public T set(int index,T newValue){                if(index<0||index>size)                     throw new ArrayIndexOutOfBoundsException();                T oldValue = elements[index];                elements[index] = newValue;                return oldValue;        }        public void print(){                for(int u=0;u<size;u++){                        System.out.println(elements[u]+",index"+u);                }        }        public static void main(String[] args) {                MyStack<Integer> stack = new MyStack<Integer>();                for(int i=0;i<10;i++){                        stack.push(i+12);                }                System.out.println(stack.size());                System.out.println(stack.remove(1));                System.out.println(stack.size());                System.out.println(stack.pop());                System.out.println(stack.size());                stack.print();        }

0 0