package sequencestack;

public class SequenceStack {
	
	private int STACK_INIT_SIZE = 5;//栈的原始大小
	private int INCREMENT =1;//栈的增量大小
	
	
	private Object []Stack = null;
	private int base;
	private int top;
	private int stacksize;
	
	/**
	 * 初始化栈
	 * */
	void initStack()
	{
		Stack = new Object[STACK_INIT_SIZE];
		base=0;
		top=0;
		stacksize=0;
	}
	
	/**
	 * 入栈
	 * */
	void push(Object o)
	{
		if(top-base>=STACK_INIT_SIZE)
		{
			System.out.println("扩充栈");
			STACK_INIT_SIZE=STACK_INIT_SIZE+INCREMENT;
			Object []temp = new Object[STACK_INIT_SIZE];
			for(int i=0;i<stacksize;i++)
			{
				temp[i]=Stack[i];
			}
			Stack=null;
			Stack=temp;
		}
		Stack[stacksize] = o;
		stacksize++;
		top++;
	}
	/**
	 * 出栈
	 * */
	Object pop()
	{
		Object o = null;
		if(top==base)
		{
			System.out.println("栈中没有元素！返回null");
		}else
		{
			o=Stack[--top];
			stacksize--;
		}
		return o;
	}
	
	/**
	 * 取栈顶元素
	 * */
	Object getTop()
	{
		Object o = null;
		if(top==base)
		{
			System.out.println("栈中没有元素！返回null");
		}else
		{
			o=Stack[top-1];
		}
		return o;
	}
	
	/**
	 * 打印栈
	 * */
	void print()
	{
		System.out.print("打印栈：");
		for(int i=0;i<stacksize;i++)
		{
			System.out.print(Stack[i]+"\t");
		}
		System.out.println();
	}
}

package sequencestack;

public class SequenceStackMain {

	public static void main(String[] args) {
		SequenceStack sStack = new SequenceStack();
		sStack.initStack();
		sStack.pop();
		sStack.push(1);
		sStack.push(2);
		sStack.push(3);
		sStack.push(4);
		sStack.push(5);
		sStack.push(6);
		sStack.push(3);
		sStack.print();
		
		sStack.pop();
		sStack.pop();
		sStack.pop();
		sStack.pop();
		sStack.print();
		
		System.out.println("取栈顶元素："+sStack.getTop());
		sStack.print();
	}

}