Code java:

/***************************************************************************************************************** * Anthony Chahine * 2/25/2013 * Quadratic Equation Grapher * * Takes 3 inputs from user, variables a, b, and c. Then plugs in those values into the formula and creates a table * of y values. Then graphs the cooresponding x and y values onto a graph using lines. *****************************************************************************************************************/ import javax.swing.JApplet; import javax.swing.JOptionPane; import java.awt.Graphics; public class Graphs extends JApplet { //creating data values into integer arrays x and y private static int[] yVals = new int[20]; private static int[] xVals = { -10,-9,-8,-7,-6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6,7,8,9,10 }; public void start(){ String a, b, c = new String(); //Strings entered by user for quadratic equation int aParsed, bParsed, cParsed = 0; //ints to be parsed from user-input strings a = JOptionPane.showInputDialog( null, "Enter integer A in Ax^2 + Bx + C = 0", "1" ); b = JOptionPane.showInputDialog( null, "Enter integer B in Ax^2 + Bx + C = 0", "2" ); c = JOptionPane.showInputDialog( null, "Enter integer C in Ax^2 + Bx + C = 0", "3" ); aParsed = Integer.parseInt( a ); bParsed = Integer.parseInt( b ); cParsed = Integer.parseInt( c ); //Calculate y values and enter them sequentially into array for ( int i = 0; i < xVals.length + 1; i ++ ){ yVals[i] = ( aParsed * ( xVals[i] * xVals[i] ) ) + ( bParsed * xVals[i] ) + cParsed; }//end of for loop /* Convert x and y values into java applet coordinates. This can only be used on a 500/500 APPLET * as it uses (250,250) as the origin. Then subtracts or adds corresponding to the proper quadrant I * II, III, and IV from 250. * Ex. (3,6) would be ( 250 + 3, 250 - 6) and (-3, -6 ) would be ( 250 - 3, 250 + 6 ) */ for( int i = 0; i < xVals.length + 1; i ++) { if ( xVals[i] >= 0 && yVals[i] >= 0 ){ xVals[i] = 250 + xVals[i]; yVals[i] = 250 - yVals[i]; }//end if loop ++ if ( xVals[i] < 0 && yVals[i] >= 0 ){ xVals[i] = 250 - xVals[i]; yVals[i] = 250 - yVals[i]; }//end if loop -+ if ( xVals[i] < 0 && yVals[i] < 0 ){ xVals[i] = 250 - xVals[i]; yVals[i] = 250 + yVals[i]; }//end if loop -- if ( xVals[i] >= 0 && yVals[i] < 0 ){ xVals[i] = 250 + xVals[i]; yVals[i] = 250 + yVals[i]; }//end if loop ++ }//end for loop }//end of start method public void paint ( Graphics g ) { super.paint(g); //Paint horizontal and vertical lines on 500/500 Applet window - Creates a grid int i = 0; for( i = 0; i <= 500; i += 50 ) { //scales by 50 per line increment == 10 lines per axis g.drawLine( i, 0, i, 500 ); g.drawLine( 0, i, 500, i ); }//end for loop //start graphing converted x and y values for( i = 0; i < xVals.length + 1; i++ ) { g.drawLine( xVals[i], yVals[i], xVals[i + 1], yVals[i + 1] ); /* Connects one point to the next point * so xVals[0] and yVals[0] connect to * xVals[1] and yVals[1] */ }//end for loop }//end of paint method }//end of class