顺序表代码

 1 import java.util.*;
 2 import java.lang.*;
 3 import java.io.*;
 4 
 5 /* Name of the class has to be "Main" only if the class is public. */
 6 class Ideone
 7 {
 8     public int top;
 9     public Object[] objArray;
10     
11     //初始化
12     public Ideone(int defaultSize)
13     {
14         objArray = new Object[defaultSize];
15         top = -1;
16     }
17     
18     //判断是否为空
19     public boolean isEmpty()
20     {
21         boolean flag = false;
22         if(top == -1)
23         {
24             flag = true;
25         }
26         return flag;
27     }
28     
29     //获取栈顶元素
30     public Object getTop()
31     {
32         if(!isEmpty())
33         {
34             return objArray[top];
35         }
36         System.out.println("栈为空");
37         return null;
38     }
39     //栈顶插入数据
40     public void push(Object obj)
41     {
42         if(top + 1 >= objArray.length)
43         {
44             System.out.println("栈已满,无法添加"+obj);
45             return ;
46         }
47         objArray[top+1] = obj;
48         top++;
49     }
50     
51     //栈顶弹出数据
52     public Object pop()
53     {
54         if(isEmpty())
55         {
56             System.out.println("栈已空");
57             return null;
58         }
59         Object obj = objArray[top];
60         objArray[top--] ="";
61         return obj;
62     }
63     
64     public static void main (String[] args) throws java.lang.Exception
65     {
66         // your code goes here
67         Ideone s = new Ideone(2);
68         s.push("a");
69         s.push("b");
70         s.push("c");
71         System.out.println(s.getTop());
72         System.out.println(s.pop());
73         System.out.println(s.getTop());
74         s.pop();
75         System.out.println(s.getTop());
76     }
77 }