Assignment 5 - GradeBookTest

// GradeBookTest.Java
// Creating and manipulating a GradeBook object.
import java.util.Scanner; // Program uses Scanner

public class GradeBookTest
{
//main method begins program execution
public static void main( String[] args )
{
    // create Scanner to obtain input from command window
    Scanner input = new Scanner( System.in );

    // create a GradeBook object and assign it to myGradeBook
    GradeBook myGradeBook = new GradeBook();

    // display initial value of courseName
    System.out.printf( "Initial course name is; %s\n\n",
    myGradeBook.getCourseName() );

    // prompt for and read course name
    System.out.println( "Please enter the course name:" );
    String theName = input.nextLine(); // read a line of text
    myGradeBook.setCourseName( theName ); // set the course name
    System.out.println(); // outputs a blank line

    // display welcome message after specifying course name
    myGradeBook.displayMessage();
} // end main
} // end class GradeBookTest

Assignment 4 - SumArray

// Fig. 6.5: SumArray.java

// Computing the sum of the elements of an array.

public class SumArray

{

public static void main(String[]args)

{

int[]array={87, 68, 94, 100, 83, 78, 85, 91, 76, 87 };

int total=0;

// add each element's value to total

for(int counter=0; counter<array.length;counter++)

total +=array[counter];

System.out.printf("Total of array elements;%d\n",total);

} // end main

} // end class SumArray

Assignment 3 - InitArray

// InitArray.java

// Calculation values to be placed into elements of an array.

public class InitArray

{

    public static void main(String[]args)

    {

        final int ARRAY_LENGTH=10; // constant

        int[] array=new int[ ARRAY_LENGTH]; // create array

        // calculate value for each array element

        for(int counter=0; counter<array.length;counter++)

        array[counter]=2+2*counter;

        System.out.printf("%s%8s\n","Index","Value"); // column heading


        // out put each array element's value

        for(int counter=0; counter<array.length;counter++)

        System.out.printf("%5d%8d\n",counter,array[counter]);

} // end main

} // end class InitArrway

Assignment 2 - DrawPanel

// Assignment 2

// DrawPanel.java

// Using drawLine to connect the corners of a panel.

import java.awt.Graphics;

import javax.swing.JPanel;

import javax.swing.JFrame;


public class DrawPanel extends JPanel

{

// draws an X from the corners of the panel

public void paintComponent( Graphics g)

{

// call paintComponent to ensure the panel displays correctly

super.paintComponent(g);

int width = getWidth(); //total width

int height=getHeight(); // total height

// draw a line from the upper.left to the upper-right

g.drawLine(0, height, width, 0);

} // end method paintComponent

public static void main(String[]args)

{

// create a panel that contains our drawing

DrawPanel panel=new DrawPanel();

// create a new frame to hold the panel

JFrame application=new JFrame();

// set the frame to exit when it is closed

application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

application.add(panel); // add the panel to the frame

application.setSize( 250, 250 ); // set the size of the frame

application.setVisible( true ); // make the frame visible

} // end main

} // end class DrawPanel

Assignment 1 - Increment

// Assignment 1

// Fig. 3.13: Increment.java

// Prefix increment and postfix increment operators.

public class Increment

{

public static void main(String[]args)

{

int c;

// demonstrate postfix increment operator

c=5; // assign 5 to c

System.out.println(c); // prints 5

System.out.println(c++); // prints 5 then postincrements

System.out.println(c); // prints 6

System.out.println(); // skip a line


// demostrate prefix increment operator

c=5; // assign 5 to c

System.out.print(c); // prints 5

System.out.println(++c); // preincrements then prints 6

System.out.println(c); // prints 6

} // end main

} // end class Increment