import java.applet.Applet;
import java.awt.*;
import java.util.*;

public class graph extends Applet
{
	char calc[] = new char[100];
	char stack[] = new char[100];
	double stackg[] = new double[100];
	int i,pt,pos,po,fj;
	int pr[] = new int[100];
	int wid=600,hei=500,bai=50;
	Graphics g;
	String st;
	TextField tx;
	List L;
	Button del;
	int nPoint = 0;
	Vector vGraphx = new Vector();
	Vector vGraphy = new Vector();

	public void init()
	{
		Panel p = new Panel();
		Panel p2 = new Panel();
		tx = new TextField("",50);
		L = new List();
		del = new Button("全て削除");
		setBackground(new Color(255,255,255));
		setLayout(new BorderLayout());
		p.setLayout(new BorderLayout());
		p.add("Center",tx);
		p.add("South",L);
		p.add("East",del);
		p.add("West",new Label("y="));
		p2.add(new Button("拡大"));
		p2.add(new Button("縮小"));
		add("South",p);
		add("North",p2);
		g = getGraphics();
	}

	public void paint(Graphics g)
	{
		int i,di,cnt;
		String buf;
		g.translate(wid/2,hei/2);
		g.drawLine(-wid/2,0,wid/2,0);
		g.drawLine(0,hei/2,0,-hei/2);
		g.drawString("0",-10,15);
		g.drawString("x",wid/2-15,-10);
		g.drawString("y",10,-hei/2+35);

		for (int iCnt = -(int)wid/bai;iCnt <= (int)wid/bai;iCnt++)
		{
			if (iCnt == 0)
				iCnt++;
			di=iCnt*bai;
			buf=String.valueOf(iCnt);
			g.drawString(buf,di-10,15);
			g.drawString(buf,-15,-di+15);
			g.drawLine(di,-5,di,5);
			g.drawLine(-5,di,5,di);
		}
		for (int iCnt = 0;iCnt < vGraphx.size();iCnt++)
		{
			drawGraph(iCnt);
		}
	}

	public void ferr()
	{
		fj = -1;
	}

	public void push(char x,int y)
	{
		stack[pos] = x;
		pr[++pos] = y;
	}

	public char pop()
	{
		if (pos <= 0)
		{
			showStatus("1.演算子の数が正しくありません。");
			pos = 0;
			ferr();
			return 0;
		}
		return stack[--pos];
	}

	public void addc(char z)
	{
		calc[pt++] = z;
	}

	public void white()
	{
		calc[pt++] = ' ';
	}

	public double chk()
	{
		return pr[pos];
	}

	public void pushg(double x)
	{
		stackg[po++] = x;
	}

	public double popg()
	{
		if (po <= 0)
		{
			showStatus("2.演算子の数が正しくありません。");
			po = 0;
			ferr();
			return 0;
		}
		return stackg[--po];
	}

	public double faci(double n)
	{
		double result = 1;
		if (n < 0)
			return 0;
		else if (n >= 0 && n <= 1)
			return 1;
		for (int e = 2;e <= n;e++)
			result *= e;
		return result;
	}

	public double log10(double i)
	{
		return Math.log(i)/Math.log(10);
	}

	public void Graph(String st)
	{
		int len,s,bx=-100,b=-100;
		char a;
		char op[] = new char[100];
		g = getGraphics();
		g.translate(wid/2,hei/2);
		st = st.substring(2);
		len = st.length();
		pos = pt = 0;
		pr[0] = 20;
		Vector vCoorx = new Vector();
		Vector vCoory = new Vector();
		nPoint = 0;

		for (i = 0;i < len;i++)
		{
			a = st.charAt(i);
			switch (a)
			{
			case '(':
			case '{':
			case '[':
				if (b == i)
				{
					white();
					if (5 >= chk())
					{
						while(5 >= chk())
							addc(pop());
					}
					push('*',5);
				}
				push(a,10);
				bx = i+1;
				break;
			case ')':
				white();
				while (stack[--pos] != '(')
				{
					pos++;
					addc(pop());
					if (pos <= 0)
					{
						showStatus("カッコの数があっていません。");
						ferr();
						return;
					}
				}
				pos++;
				pop();
				b = i+1;
				break;
			case '}':
				white();
				while (stack[--pos] != '{')
				{
					pos++;
					addc(pop());
					if (pos <= 0)
					{
						showStatus("カッコの数があっていません。");
						ferr();
						return;
					}
				}
				pos++;
				pop();
				b = i+1;
				break;
			case ']':
				white();
				while (stack[--pos] != '[')
				{
					pos++;
					addc(pop());
					if (pos <= 0)
					{
						showStatus("カッコの数があっていません。");
						ferr();
						return;
					}
				}
				pos++;
				pop();
				b = i+1;
				break;

			case '+':
			case '-':
				if (i == 0 || bx == i)
				{
					addc('0');
					white();
					push(a,3);
					break;
				}
				white();
				if (8 >= chk())
				{
					while (8 >= chk())
						addc(pop());
				}
				push(a,8);
				bx = i+1;
				break;
			case '*':
			case '･':
			case '/':
				white();
				if (5 >=chk())
				{
					while (5 >= chk())
						addc(pop());
				}
				push(a,5);
				bx = i+1;
				break;
			case '^':
				white();
				if (2 >= chk())
				{
					while (2 >= chk())
						addc(pop());
				}
				push(a,2);
				bx = i+1;
				break;

			default:
				if (a >= 'a' && a <= 'w' || a == 'z')
				{
					white();
					op[0] = a;
					s = 1;
					if (b == i)
					{
						white();
						if (5 >= chk())
						{
							while (5 >= chk())
								addc(pop());
						}
						push('*',5);
					}
					while ((a=st.charAt(++i)) >= 'a' && a <= 'w' || a == 'z')
					{
						op[s] = a;
						s++;
					}
					a = st.charAt(--i);
					op[s] = 0;
					String ops = new String(op);
					ops = ops.substring(0,s);
					if (ops.equals("root"))
						push('r',7);
					else if (ops.equalsIgnoreCase("abs"))
						push('b',7);
					else if (ops.equalsIgnoreCase("sin"))
						push('s',7);
					else if (ops.equalsIgnoreCase("sinh"))
						push('S',7);
					else if (ops.equalsIgnoreCase("asin"))
						push('a',7);
					else if (ops.equalsIgnoreCase("cos"))
						push('c',7);
					else if (ops.equalsIgnoreCase("cosh"))
						push('C',7);
					else if (ops.equalsIgnoreCase("acos"))
						push('A',7);
					else if (ops.equalsIgnoreCase("tan"))
						push('t',7);
					else if (ops.equalsIgnoreCase("tanh"))
						push('T',7);
					else if (ops.equalsIgnoreCase("atan"))
						push('X',7);
					else if (ops.equalsIgnoreCase("e"))
						push('e',7);
					else if (ops.equalsIgnoreCase("log"))
						push('l',7);
					else if (ops.equalsIgnoreCase("ln"))
						push('L',7);
					else if (ops.equalsIgnoreCase("pi")){
						b = i+1;
						addc('p');
					}
					else
					{
						showStatus("未定義の文字列があります。");
						ferr();
						return;
					}
					for (int e = 0;e < 100;e++)
						op[e] = ' ';
				}	//if
				else if (a >= '0' && a <='9')
				{
					b = i+1;
					addc(a);
				}
				else if (a == 'x' || a == 'X')
				{
					if (b == i)
					{
						white();
						if (5 >= chk())
						{
							while(5 >=chk())
								addc(pop());
						}
						push('*',5);
					}
					b = i+1;
					addc('x');
				}
				else if (a == 'y' || a == 'Y')
				{
					showStatus("yは使用しないでください。");
					ferr();
					return;
				}
				else if (a == '.' || a == '!')
					addc(a);
				else if (a == ' ')
				{
					bx++;
					b++;
				}
				else
				{
					showStatus("計算できない文字が含まれています。半角で式を入力してください。");
					ferr();
					return;
				}
			}	//switch
			if (fj == -1)
				return;
		}	//for
		if (pos > 0)
		{
			while (pos > 0)
			{
				addc(pop());
				if (stack[pos] == '(')
				{
					showStatus("カッコの数があっていません。");
					ferr();
					return;
				}
			}
		}
		if (fj == -1)
			return;

		int dd,j,jj;
		char c;
		double m,x,y,dx,dy;
		dx = dy = jj = 0;
		for (m = -wid/bai;m <= wid/bai;m += 0.01)
		{
			po = 0;
			for (j = 0;j < pt;j++)
			{
				double x1,x2;
				c = calc[j];
				if (c >= '0' && c <= '9')
				{
					x1 = c-'0';
					while ((c = calc[++j]) >= '0' && c <= '9')
						x1 = 10*x1+(c-'0');
					if (c == '.'){
						x2 = 1.0;
						while ((c = calc[++j]) >= '0' && c <= '9')
						{
							x2 = x2/10.0;
							x1 = x1+x2*(c-'0');
						}
					}
					pushg(x1);
					c = calc[--j];
				}

				switch (c)
				{
				case '+':
					pushg(popg()+popg());
					break;
				case '-':
					x1 = popg();
					pushg(popg()-x1);
					break;
				case '*':
					pushg(popg()*popg());
					break;
				case '/':
					x1 = popg();
					if (x1 != 0.0)
						pushg(popg()/x1);
					else{
						showStatus("0では割れません。");
						ferr();
						return;
					}
					break;
				case '^':
					x1 = popg();
					pushg(Math.pow(popg(),x1));
					break;
				case '!':
					pushg(faci(popg()));
					break;
				case 'x':
					pushg(m);
					break;

				case 'r':
					x1 = popg();
					fj = 0;
					if (x1 < 0.0)
					{
						fj = -2;
						jj = 0;
						break;
					}
					pushg(Math.sqrt(x1));
					break;
				case 'b':
					pushg(Math.abs(popg()));
					break;
				case 's':
					pushg(Math.sin(popg()));
					break;
				case 'S':
					x1 = popg();
					pushg((Math.exp(x1)-Math.exp(-x1))/2);
					break;
				case 'a':
					pushg(Math.asin(popg()));
					break;
				case 'c':
					pushg(Math.cos(popg()));
					break;
				case 'C':
					x1 = popg();
					pushg((Math.exp(x1)+Math.exp(-x1))/2);
					break;
				case 'A':
					pushg(Math.acos(popg()));
					break;
				case 't':
					pushg(Math.tan(popg()));
					break;
				case 'T':
					x1 = popg();
					pushg((Math.exp(x1)-Math.exp(-x1))/(Math.exp(x1)+Math.exp(-x1)));
					break;
				case 'X':
					pushg(Math.atan(popg()));	
					break;
				case 'e':
					pushg(Math.exp(popg()));
					break;
				case 'l':
					pushg(log10(popg()));
					break;
				case 'L':
					pushg(Math.log(popg()));
					break;
				case 'p':
					pushg(3.1415926535897932385);
					break;
				}
				if (fj == -1)
					return;
			}	//for
			if (fj != -2)
			{
				x = m;
				y = popg();
				if (y > 299)
					y = 299;
				else if (y < -299)
					y = -299;
				x = x*bai;
				y = -y*bai;
				if (y > 100*bai && (dy < -100*bai || dy == 0) ||
					y < -100*bai && (dy > 100*bai || dy == 0))
				{
					Integer dbx = new Integer((int)x);
					Integer dby = new Integer((int)y);
					vCoorx.addElement(dbx);
					vCoory.addElement(dby);
				}
				else
				{
					if (jj != 0)
					{
						Integer dbx = new Integer((int)x);
						Integer dby = new Integer((int)y);
						vCoorx.addElement(dbx);
						vCoory.addElement(dby);
						nPoint++;
					}
					jj++;
				}
				dx = x;
				dy = y;
			}
		}	//for
		for (i = 0;i < 100;i++)
		{
			calc[i] = ' ';
			stack[i] = ' ';
			pr[i] = ' ';
			stackg[i] = ' ';
		}
		vGraphx.addElement(vCoorx);
		vGraphy.addElement(vCoory);
	}	//Graph

	public boolean action(Event e,Object o)
	{
		String buf = "";
		if (e.target instanceof TextField)
		{
			st = (String)o;
			st = st.toLowerCase();
			if (st.length() != 0)
			{
				fj = 0;
				st = "y="+st;
				Graph(st);
				if (fj == 0)
				{
					L.addItem(st);
					tx.setText("");
					st = "";
				}
			}
		}
		else if (e.target instanceof Button)
		{
			Button b = (Button)e.target;
			if ("全て削除".equals(b.getLabel()))
			{
				L.clear();
				tx.setText("");
				vGraphx.removeAllElements();
				vGraphy.removeAllElements();
			}
			else if ("拡大".equals(b.getLabel()))
			{
				if (bai < 100)
				{
					bai += 10;
					vGraphx.removeAllElements();
					vGraphy.removeAllElements();
					for (int iCnt = 0;iCnt < L.getItemCount();iCnt++)
					{
						buf=L.getItem(iCnt);
						Graph(buf);
					}
				}
				else
					return true;
			}
			else if ("縮小".equals(b.getLabel()))
			{
				if (bai > 20)
				{
					bai -= 10;
					vGraphx.removeAllElements();
					vGraphy.removeAllElements();
					for (int iCnt = 0;iCnt < L.getItemCount();iCnt++)
					{
						buf=L.getItem(iCnt);
						Graph(buf);
					}
				}
				else
					return true;
			}
		}
		repaint();
		return true;
	}
	
	public void drawGraph(int i)
	{
		int xPoint[] = new int[nPoint];
		int yPoint[] = new int[nPoint];
		Integer ix,iy;
		
		Vector vCoorx = (Vector)vGraphx.elementAt(i);
		Vector vCoory = (Vector)vGraphy.elementAt(i);
		
		for (int ipos = 0;ipos < nPoint;ipos++)
		{
			ix = (Integer)vCoorx.elementAt(ipos);
			iy = (Integer)vCoory.elementAt(ipos);
			xPoint[ipos] = ix.intValue();
			yPoint[ipos] = iy.intValue();
		}
		g = getGraphics();
		g.translate(wid/2,hei/2);
		g.drawPolyline(xPoint,yPoint,nPoint);
	}
}