java中常用的栈操作
top赋初值是-1，入栈先做top++，出栈先赋值后top–
如图：

示例代码：

先写一个接口类

public interface IStack {

void push(Object obj) throws Exception;
Object pop() throws Exception;
boolean isEmpty();

}

接口的实现

public class MyStack implements IStack {

private int top = -1;
private Object arrStr[] = new Object[5];

public void push(Object obj) throws Exception {

    if (top >= arrStr.length - 1) {
        throw new Exception("超出栈顶");
    } else {
        top++;
        arrStr[top] = obj;
    }
}

public Object pop() throws Exception {

    if (top < 0) {
        throw new Exception("超出栈底");
    } else {
        Object obj = arrStr[top];
        arrStr[top]=null;
        top--;
        return obj;
    }

}

public boolean isEmpty() {

    return top == -1;
}

public void print() {
    if (!isEmpty()) {
        for (int i = 0; i <= top; i++) {
            System.out.println(arrStr[i]);
        }
    } else {
        System.out.println("空");
    }
}

}

测试类

public class TestStack {
public static void main(String[] args) {
MyStack ms=new MyStack();
try {
ms.push(“aaa”);
ms.push(“bbb”);
ms.push(“ccc”);
ms.push(“ddd”);
ms.push(“eee”);
//ms.push(“eee”);

        ms.pop();
        ms.pop();
        ms.pop();
        //ms.pop();
        //ms.pop();

        System.out.println(ms.isEmpty());
        ms.print();



    } catch (Exception e) {
        e.printStackTrace();
    }
}

}