栈最大的一个特点就是先进后出(FILO—First-In/Last-Out)。
/**
* 栈:后进先出
* Created by fred on 2018/7/31.
*/
public class MyStack {
private int[] elements;
private int size;
private final int DEFAULT_CAPACITY = 2;
public MyStack(){
elements = new int[DEFAULT_CAPACITY];
}
//判断是否为空
public boolean isEmpty(){
return size == 0;
}
//获取栈的长度
public int getSize(){
return size;
}
//数据入栈
public void push(int value){
if(size >= elements.length){
int[] tmp = new int[elements.length * 2];
System.arraycopy(elements, 0, tmp, 0, elements.length);
elements = tmp;
}
elements[size++] = value;
}
//出栈
public int pop(){
if(isEmpty()){
System.out.println("栈为空");
return -1;
}
else {
return elements[--size];
}
}
}