demo.java

学习数据结构的最好辅助工具,快速帮助你熟悉数据结构的相关技术

import java.awt.*;
public class Demo extends Canvas
{
	private int sleepTime = 40;
	private boolean m_initiated = false, m_hasError = false;
	private char m_data[] = new char[10];
	private int m_stackTop = 0;
	private String m_err;
	
	public void reset()
	{
		m_initiated = false; m_hasError = false;
		repaint();
	}
	
	public void init()
	{
		m_initiated = true; m_stackTop = 0;
		repaint();
	}
	
	public boolean push(char c)
	{
		if( m_stackTop>=10 )
		{
			error("栈溢出,表达式太长!");
			repaint();
			return false;
		}
		else
		{
			m_data[m_stackTop] = c;
			m_stackTop ++;
			repaint();
			return true;
		}
	}
	
	public boolean isEmpty()
	{
		return (m_stackTop==0);
	}
	
	public char pop()
	{
		if( m_stackTop==0 )
		{
			error("已到栈顶,表达式有误!");
			repaint();
			return ' ';
		}
		m_stackTop --;
		repaint();
		return m_data[m_stackTop];
	}
	
	public char getTop()
	{
		if( m_stackTop == 0) return ' ';
		return m_data[m_stackTop-1];
	}
	
	public void paint(Graphics p1)
	{
		if(m_hasError) p1.drawString(m_err, 50, 100);
		else if(m_initiated)
		{
			p1.drawLine(50, 100, 300, 100);
			p1.drawLine(50, 130, 300, 130);
			for(int i=0;i<=10;i++) p1.drawLine(50+i*25, 100, 50+i*25, 130);
			for(int i=0;i<m_stackTop;i++) p1.drawChars(m_data, i, 1, 285-i*25, 120);
		}
	}
	
	public void error(String s)
	{
		m_err = s;
		m_hasError = true;
	}
}