line graph in java, graphics in java or java graph programming

Demo Line Graph

//Display a line graph representing the number of A's, B's, C's, D's and F's //on the Java Programming Final Examination import java.awt.*; import BreezyGUI.*; public class lineonly extends GBFrame {    //Establish the placement of the fields for user entry    Label LabelA = addLabel("A", 1,1,1,1);    IntegerField FieldA = addIntegerField(0,1,2,1,1);    Label LabelB = addLabel("B", 1,3,1,1);    IntegerField FieldB= addIntegerField(0,1,4,1,1);    Label LabelC = addLabel("C", 1,5,1,1);    IntegerField FieldC = addIntegerField(0,1,6,1,1);    Label LabelD = addLabel("D", 1,7,1,1);    IntegerField FieldD = addIntegerField(0,1,8,1,1);    Label LabelF = addLabel("F", 1,9,1,1);    IntegerField FieldF = addIntegerField(0,1,10,1,1);    //Establish a drop down menu for the drawing    //Right now we only have one choice -- Line    MenuItem lineChoice = addMenuItem("Graph", "Line");   //Establish variables for this program    int numberOfScores = 5;    int Xleft = 100;    int Xright = 300;    int Ytop = 100;  // The y-value entries can be up to 250-100=150.    int Ybottom = 250;    int totalX, totalY;    int[ ] scores;    char graphChoice;    //Constructor to establish the initial values in the program    public lineonly ( )    {        scores = new int[numberOfScores];        for (int i = 0; i < scores.length;  i++)                  scores[ i ] = 0;       totalX = Xright - Xleft + 1;       totalY = Ybottom - Ytop + 1;       graphChoice = 'L';    }    //Allow for the menu choices    //Remember, we only have one choice right now    public void menuItemSelected(MenuItem item)    {        if (item == lineChoice)        graphChoice = 'L';       repaint();    }   //Establish the paint method    public void paint (Graphics g)    {         getInputData();         g.setColor (Color.red);   //set color of the graph         drawLineGraph(g);         g.drawString("Java Grades", 170, 290); // title    }   //Get input from user    public void getInputData()    {        scores[0] = FieldA.getNumber();        scores[1] = FieldB.getNumber();        scores[2] = FieldC.getNumber();        scores[3] = FieldD.getNumber();        scores[4] = FieldF.getNumber();    }     //Draw the line graph    public void drawLineGraph(Graphics g)    {         drawAxes(g);         int i, x1, y1, x2, y2, largestNumber, xIncrement, yIncrement;        //Compute the x and y increments        largestNumber = findLargest (scores);        xIncrement = totalX / numberOfScores;        if (largestNumber ==0)                yIncrement = 0;        else                yIncrement = totalY / largestNumber;       //Set the initial origin point        x1 = Xleft;        y1 = Ybottom;       //Compute and plot the data points        for(i=0; i < numberOfScores; i++)       {           x2 = getXCoordinate(i+1, xIncrement);           y2 = getYCoordinate(scores[i], yIncrement);           g.fillOval(x2, y2, 5, 5);           g.drawLine(x1, y1, x2, y2);           x1 = x2;           y1 = y2;        }       //Label x - axes with grade choices       String [ ] label = {"A", "B", "C", "D", "F"};       for (i=1; i<=numberOfScores; i++)           g.drawString(label[i-1], 100+ i*xIncrement, 270);       //Label y - axes with quantity of each grade       int topy;       if(largestNumber%10==0)            topy=largestNumber;       else            topy = (largestNumber/10+1)*10;             // i = i+5 controls y value label -- adjust for size of data       for (i = 0; i <= topy; i = i+5)       {         g.drawString(String.valueOf(i), 70, Ybottom-i*yIncrement+5);       }    }   //Draw the axes for the graph    public void drawAxes (Graphics g)    {         g.drawLine(Xleft, Ytop, Xleft, Ybottom);         g.drawLine(Xleft, Ybottom, Xright, Ybottom);    }   //Determining x coordinate    public int getXCoordinate(int i, int xIncrement)    {        return Xleft + xIncrement *i;    }    //Determining y coordinate    public int getYCoordinate(int numStudents, int yIncrement)    {        return Ybottom - yIncrement * numStudents;    }    //Finding the largest value in the array    public int findLargest(int [ ] a)    {        int location = 0;       for( int i = 1; i < a.length; i++)                  if(a[i] > a[location])                        location = i;      return a[location];    }   //Main    public static void main(String[ ] args)    {          Frame frm = new lineonly();          frm.setSize (400, 300);         frm.setVisible (true);    } }