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Need help with calling the toString method from my class into my main method...Plz HELP

Posted on 2006-11-18
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Last Modified: 2010-03-31
Im writing a program where you input four coefficients and it evaluates x for f(x) and then prints a table.....Before this table is printed however, I need to call the equasion from a toString method and print it into output using System.out.println(toString). Everytime I compile the main program i get this error

Poly.java:43: cannot find symbol
symbol  : method toString(java.lang.String)
location: class Polynomial
System.out.println(pn.toString(result));
                     ^

The Class compiles fine....

Here is my code....
(MAIN METHOD)

import java.util.Scanner;
import java.text.DecimalFormat;

public class Poly
{
      public static void main (String[] args)
            {
double c4,c3,c2,c1,c0,x,interval,xvalue;
int ptnumber,counter;
String result;

DecimalFormat fmt = new DecimalFormat ("0.##");

Scanner scan = new Scanner (System.in);

System.out.print ("Enter the coefficient of x^4(0.0 if none:");
c4 = scan.nextDouble();

System.out.print ("Enter the coefficient of x^3(0.0 if none:");
c3 = scan.nextDouble();

System.out.print ("Enter the coefficient of x^2(0.0 if none:");
c2 = scan.nextDouble();

System.out.print ("Enter the coefficient of x^1(0.0 if none:");
c1 = scan.nextDouble();

System.out.print ("Enter the constant:");
c0 = scan.nextDouble();

System.out.print ("Enter the starting value of x:");
x = scan.nextDouble();

System.out.print ("Enter the number of points to be graphed(Integer):");
ptnumber = scan.nextInt();

System.out.print ("Enter the interval between points:");
interval = scan.nextDouble();


Polynomial pn = new Polynomial(c4, c3, c2, c1, c0);

System.out.println(pn.toString(result));

System.out.println("x      | f(x)");
System.out.println("----------");
counter = 0;
while (counter < ptnumber)
{

System.out.println(x            +"      | "+fmt.format(pn.evaluate(x)));

x = (x + interval);
counter++;
}
      }
}

(POLY CLASS)

import javax.swing.JPanel;
import java.awt.*;
import java.text.DecimalFormat;


import java.text.DecimalFormat;
public class Polynomial
{
   double coeff4, coeff3, coeff2, coeff1, constant;
   public Polynomial(double c4, double c3, double c2, double c1, double c0)
      {
            coeff4 = c4;
            coeff3 = c3;
            coeff2 = c2;
            coeff1 = c1;
            constant = c0;
      
      }
      
      public double evaluate(double x)
      {
                  
            double xsq = x*x;
          return (coeff4*xsq*xsq + coeff3*xsq*x + coeff2*xsq + coeff1*x + constant);
      
      }
      
      public String toString()
      {
         //String result = "";
            String result =  (coeff4 + "*x^4 + " + coeff3 + "*x^3 + " + coeff2 + "*x^2 + " + coeff1 + "*x^1 + " + constant);
            return result;
             
  }
 
 
     
  public void draw(Graphics page, int xPixels, int yPixels)
{
    final int NUM = 11;
    final double INTERVAL = 0.5;
    final double XSTART = 0.0;

    final int XMARGIN = 70;
    final int XUSABLEPIXELS = xPixels - 2*XMARGIN;
    final int XINTERVALPIXELS = XUSABLEPIXELS/(NUM - 1);
    final int YMARGIN =40;
    final int YUSABLEPIXELS = yPixels - 2*YMARGIN;
      
        // Label the graph
    page.drawString("Graph of f(x) = " + toString(), XMARGIN + 20, YMARGIN);

    // Draw the x axis and put in hash marks
    page.drawLine(XMARGIN, yPixels - YMARGIN, xPixels - XMARGIN, yPixels - YMARGIN);
    for ( int i = 0; i < NUM; i++ )
        page.drawLine(XMARGIN + i * XINTERVALPIXELS, yPixels - YMARGIN, XMARGIN + i * XINTERVALPIXELS, yPixels - YMARGIN + 5);
             
       DecimalFormat twoPlaces = new DecimalFormat("0.00");

    // Label the x axis
    for (int i = 0; i < NUM; i++)
    {
        page.drawString( twoPlaces.format(XSTART + i * INTERVAL), 3 * XMARGIN / 4 + i * XINTERVALPIXELS, yPixels - YMARGIN/2);
    }

    // Draw the y axis
    page.drawLine(XMARGIN, YMARGIN, XMARGIN, yPixels - YMARGIN);

    // Label the y axis and put in hash marks
    final double YMIN = 0.0;
    final double YINTERVAL = 100.0;
    final int YINTERVALPIXELS = YUSABLEPIXELS / 10;

    for (int i = 0; i < NUM; i++)
    {
        page.drawString(twoPlaces.format(YMIN + i * YINTERVAL), XMARGIN / 4, yPixels - i * YINTERVALPIXELS - YMARGIN);
        page.drawLine(XMARGIN, yPixels - YMARGIN - i * YINTERVALPIXELS, XMARGIN - 5, yPixels - YMARGIN - i * YINTERVALPIXELS);
    }

    // your code
   }
}


             
        
   
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Question by:lusius188
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1 Comment
 
LVL 23

Accepted Solution

by:
Ajay-Singh earned 250 total points
ID: 17972509
the default implementation doesn't take any argument, if you want toString of result varaible, you should just call

result.toString()
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