node.java

Binary Expression Tree show in SVG

//
//
// Group 5
//
import java.lang.*;
import java.util.*;
import java.io.*;
public class Node {
    static final int NUMBER = 0, OPERATOR = 1;   // values for kind.                                      
    int kind;       // type of node
    double number;  // The value in a node
    char op;        // The operator in a node
    Node left;		// left node
    Node right;		// right node
    static int lx = 1, rx = 1, ly = 0, ry = 0, xor = 512, yor = 50, xtx = 508, ytx = 56, a = 0;

    Node(double val) {
       kind = NUMBER;
       number = val;
    }
    
    Node(char val) {
       kind = OPERATOR;
       this.op = val;
    }    

    Node(char op, Node right, Node left) {
       kind = OPERATOR;
       this.op = op;
       this.left = left;
       this.right = right;
    }
	
	public static void preoder(Node node)throws IOException{
		if ( node.kind == NUMBER) {
			System.out.print(node.number + " ");
			//noderTest(node);
		}else{
			System.out.print(node.op + " ");
			//noderTest(node);
		}
		if(node.left!=null)
			preoder(node.left);
		if(node.right!=null)
			preoder(node.right);
	}


	public static void noderTest(Node node)throws IOException{
		FileWriter svg2 = new FileWriter("tree.svg",true);
		BufferedWriter out2 = new BufferedWriter(svg2);
		if ( node.kind == NUMBER) {
			out2.write("<circle cx=\""+xor+"\" cy=\""+yor+"\" r=\"20\" fill=\"red\" stroke=\"black\" stroke-width=\"a\"/> <text x=\""+xtx+"\" y=\""+ytx+"\" stroke=\"black\" font-size=\"14\" font-family=\"Verdana\">"+node.number+"</text>");   
	     }
	     else { 
			out2.write("<circle cx=\""+xor+"\" cy=\""+yor+"\" r=\"20\" fill=\"green\" stroke=\"black\" stroke-width=\"a\"/> <text x=\""+xtx+"\" y=\""+ytx+"\" stroke=\"black\" font-size=\"14\" font-family=\"Verdana\">"+node.op+"</text>");
		 }		
		if (node.left != null) {
			lx++;ly++;
			a = 0;
			out2.write("<line x1 = \""+(xor-13)+"\" y1 = \""+(yor+13)+"\" x2 = \""+((xor - 300/lx)+13)+"\" y2 = \""+((yor + ly*50)-13)+"\" stroke = \"black\" stroke-width = \"3\"/>");
			xor = xor - 300/lx;
			yor = yor + ly*50;
			xtx = xtx - 300/lx;
			ytx = ytx + ly*50;
			noderTest(node.left);
		}
		if (node.right != null) {
			if (a == 0)
			{
				xor = xor + 2*(300/lx);
				xtx = xtx + 2*(300/lx);
				out2.write("<line x1 = \""+(xor-13)+"\" y1 = \""+(yor-13)+"\" x2 = \""+((xor - 300/lx)+13)+"\" y2 = \""+((yor - ly*50)+13)+"\" stroke = \"black\" stroke-width = \"3\"/>");
				a++;
			}
			else{
				lx--;
				if (lx == 2)
				{
					xor = 512 + 300/lx;
					xtx = 512 + 300/lx;
					yor = yor - ly*50;
					ytx = ytx - ly*50;
					out2.write("<line x1 = \""+(xor-13)+"\" y1 = \""+(yor-13)+"\" x2 = \""+((xor - 300/lx)+15)+"\" y2 = \""+((yor - ly*50)+63)+"\" stroke = \"black\" stroke-width = \"3\"/>");
				}
				else{
					xor = xor + 300/lx;
					yor = yor - ly*50;
					xtx = xtx + 300/lx;
					ytx = ytx - ly*50;
					out2.write("<line x1 = \""+(xor-13)+"\" y1 = \""+(yor-13)+"\" x2 = \""+((xor - 300/lx)+40)+"\" y2 = \""+((yor - ly*50)+60)+"\" stroke = \"black\" stroke-width = \"3\"/>");
				}
					ly--;
				}		
		noderTest(node.right);
		}
		out2.close();
	}
	// Return the value of the expression
	static double getValue( Node node ) throws IOException {
		
	     if ( node.kind == NUMBER) {
	        return node.number;
	     }
	     else { 
	        double leftVal = getValue( node.left );
	        double rightVal = getValue( node.right );
	        switch(node.op) {
	           case '+':  return leftVal + rightVal;
	           case '-':  return leftVal - rightVal;
	           case '*':  return leftVal * rightVal;
	           case '/':  return leftVal / rightVal;
	           default:   return Double.NaN;  // return Not a Number
	        }
	     }
	  }

	public static void main (String[] args) throws IOException {	

		Node t5 = new Node(4);
		Node t6 = new Node(9);
		Node t7 = new Node(5);
		Node t8 = new Node(3);
		Node t9 = new Node(4);
		Node t4 = new Node('*', t9, t8);
		Node t2 = new Node('+', t5, t4);
		Node t3 = new Node('-', t7, t6);
		Node t1 = new Node('/', t3, t2);
		
		FileWriter svg = new FileWriter("tree.svg",true);
		BufferedWriter out = new BufferedWriter(svg);
		out.write("<?xml version=\"1.0\" standalone=\"no\"?>");	
		out.write("<svg width=\"100%\" height=\"100%\" version=\"1.1\" xmlns=\"http://www.w3.org/2000/svg\">");	
		out.close();
		
		noderTest(t1);
		preoder(t1);
		
		FileWriter svg3 = new FileWriter("tree.svg",true);
		BufferedWriter out3 = new BufferedWriter(svg3);
		out3.write("</svg>");
		out3.close();
		
		double value = getValue(t1); // get Value
		System.out.println("Result = " + value); // show value
	} 
}