Using Object

// Java0601.java// This program demonstrates that the methods of a class are not always // accessible, like they were with the <Math> class. In this case an// attempt is made to use methods of the <Bank> class without success.

public class Java0601{

public static void main (String args[]){

System.out.println("\nJAVA0601.JAVA\n");Bank.checkingDeposit(1000.0);Bank.savingsDeposit(5000.0);System.out.println("Checking balance: " + Bank.getChecking());System.out.println("Savings balance: " + Bank.getSavings());System.out.println();

}}

// Java0602.java// This program creates two Bank objects, called tom and sue. // Each object stores its own Bank information.



System.out.println("\nJAVA0602.JAVA\n");Bank tom;tom = new Bank();Bank sue;sue = new Bank();tom.checkingDeposit(1000.0);tom.savingsDeposit(5000.0);sue.checkingDeposit(1500.0);sue.savingsDeposit (4000.0);System.out.println("Tom's checking balance: " + tom.getChecking());System.out.println("Tom's savings balance: " + tom.getSavings());System.out.println("Sue's checking balance: " + sue.getChecking());System.out.println("Sue's savings balance: " + sue.getSavings());System.out.println();

}}

Data Types & Variables vs. Classes & Objects

You have seen program statements like:

In this case, int is the data type and x is the variable.

The previous program had this statement:

In this case, Bank is the data type and tom is the variable ; however, Bank is a special data type called a class, and tom is a special variable called an object.

int x;

Bank tom;

// Java0603.java This program demonstrates how an object can be constructed with a specified// initial balance in checking and savings. Most Java classes have multiple// constructors to create objects for multiple situations.public class Java0603{


System.out.println("\nJAVA0603.JAVA\n");Bank tom; tom = new Bank(5000.0,10000.0);Bank sue; sue = new Bank(3000.0,15000.0);

System.out.println("Tom's checking balance: " + tom.getChecking());System.out.println("Tom's savings balance: " + tom.getSavings());System.out.println("Sue's checking balance: " + sue.getChecking());System.out.println("Sue's savings balance: " + sue.getSavings());System.out.println();System.out.println("Tom makes a $1000.00 checking withdrawal");tom.checkingDeposit(1000.0);System.out.println("Tom makes a $2000.00 savings withdrawal");tom.savingsDeposit(2000.0);System.out.println("Sue makes a $1500.00 checking deposit");sue.checkingDeposit(1500.0);System.out.println("Sue makes a $3000.00 savings deposit");sue.savingsDeposit(3000.0);System.out.println();System.out.println("Tom's checking balance: " + tom.getChecking());System.out.println("Tom's savings balance: " + tom.getSavings());System.out.println("Sue's checking balance: " + sue.getChecking());System.out.println("Sue's savings balance: " + sue.getSavings()); System.out.println();

}}

The Preferred WayLet us think back to Chapter 3. You were shown statements that define and initialize variables like:

But then, you were shown that it is better to define and initialize your variables in one statement like this:

The same thing applies to creating objects. The previous program first declared an object, and then constructed it, with 2 separate statements:

As before, it is better to combine these 2 statements into one. We can declare and construct the object in one statement like this:

int x;x = 5;

int x = 5;

Bank tom;tom = new Bank(5000.0,10000.0);

Bank tom = new Bank(5000.0,10000.0);

// Java0604.java// This program demonstrates how an object can be declared and defined all in one statement.// It also shows the checkingWithdrawal and savingsWithdrawal method.public class Java0604{


System.out.println("\nJAVA0604.JAVA\n");Bank tom = new Bank(5000.0,10000.0);Bank sue = new Bank(3000.0,15000.0);

System.out.println("Tom's checking balance: " + tom.getChecking());System.out.println("Tom's savings balance: " + tom.getSavings());System.out.println("Sue's checking balance: " + sue.getChecking());System.out.println("Sue's savings balance: " + sue.getSavings());System.out.println();System.out.println("Tom makes a $1000.00 checking withdrawal");tom.checkingWithdrawal(1000.0);System.out.println("Tom makes a $2000.00 savings withdrawal");tom.savingsWithdrawal(2000.0);System.out.println("Sue makes a $1500.00 checking withdrawal");sue.checkingWithdrawal(1500.0);System.out.println("Sue makes a $3000.00 savings withdrawal");sue.savingsWithdrawal(3000.0);System.out.println();System.out.println("Tom's checking balance: " + tom.getChecking());System.out.println("Tom's savings balance: " + tom.getSavings());System.out.println("Sue's checking balance: " + sue.getChecking());System.out.println("Sue's savings balance: " + sue.getSavings());System.out.println();

}}

// Java0605.java// This program demonstrates how to "right justify" integers with an object// of the <DecimalFormat> class and the <format> method.

import java.text.DecimalFormat; // necessary to use DecimalFormat class



System.out.println("\nJAVA0605.JAVA\n");DecimalFormat output = new DecimalFormat("00000");System.out.println(output.format(1));System.out.println(output.format(12));System.out.println(output.format(123));System.out.println(output.format(1234));System.out.println(output.format(12345));System.out.println(output.format(123456));System.out.println(output.format(1234567));System.out.println();

}}

// Java0606.java// This program demonstrates how to insert commas in numerical output// with a <DecimalFormat> object.

import java.text.DecimalFormat;



System.out.println("\nJAVA0606.JAVA\n");DecimalFormat output = new DecimalFormat("0,000,000");System.out.println(output.format(1));System.out.println(output.format(12));System.out.println(output.format(123));System.out.println(output.format(1234));System.out.println(output.format(12345));System.out.println(output.format(123456));System.out.println(output.format(1234567));System.out.println();

}}

Try this!Change the

DecimalFormat to “0,000” and make the last number

1234567890

// Java0607.java// This program demonstrates how to display US currency amounts.// Additionally note how the <format> methods rounds off to the nearest penny.// Also, note that the object does not have to be called "output".

import java.text.DecimalFormat;



System.out.println("\nJAVA0607.JAVA\n");DecimalFormat money = new DecimalFormat("$0.00");System.out.println(money.format(1));System.out.println(money.format(12.2));System.out.println(money.format(123.32));System.out.println(money.format(1234.432));System.out.println(money.format(12345.543));System.out.println(money.format(123456.654));System.out.println(money.format(1234567.7651));System.out.println();

}}

// Java0608.java// This program demonstrates how to control rounding off to a specified// number of digits beyond the decimal point.// It also shows that multiple DecimalFormat objects can be in the same program.import java.text.DecimalFormat;public class Java0608{


System.out.println("\nJAVA0608.JAVA\n");DecimalFormat output1 = new DecimalFormat("0.0");DecimalFormat output2 = new DecimalFormat("0.00");DecimalFormat output3 = new DecimalFormat("0.000");DecimalFormat output4 = new DecimalFormat("0.0000");DecimalFormat output5 = new DecimalFormat("0.00000");DecimalFormat output6 = new DecimalFormat("0.000000");DecimalFormat output7 = new DecimalFormat("0.0000000");DecimalFormat output8 = new DecimalFormat("0.00000000");System.out.println(Math.PI);System.out.println(output1.format(Math.PI));System.out.println(output2.format(Math.PI));System.out.println(output3.format(Math.PI));System.out.println(output4.format(Math.PI));System.out.println(output5.format(Math.PI));System.out.println(output6.format(Math.PI));System.out.println(output7.format(Math.PI));System.out.println(output8.format(Math.PI)); System.out.println();

}}

// Java0609.java// This program demonstrates the <drawString> method.// With <Expo.drawString(g,"Hello World",x,y)>, the string // Hello World will be displayed starting at the [x,y] pixel coordinate. import java.awt.*;import java.applet.*; public class Java0609 extends Applet{

public void paint(Graphics g){

Expo.drawString(g,"Top-Left-Hand Corner",40,40);Expo.drawString(g,"Top-Right-Hand Corner",840,40);Expo.drawString(g,"Bottom-Left-Hand Corner",40,640);Expo.drawString(g,"Bottom-Right-Hand Corner",820,640);Expo.drawString(g,"Middle",480,330);

}}

The drawString MethodExpo.drawString(g,"Hello There!", x, y);

Draws any String starting at coordinate (x,y).

Hello There!x, y

// Java0610.java// This program introduces the <setFont> method. setFont requires a Name, Style and Size.// Name is either "Courier", "TimesRoman", "Arial", or any other available font.// Style is either Font.PLAIN, Font.BOLD, Font.ITALIC or Font.BOLD+Font.Italic.// Size is the point size value of the Font.

import java.awt.*;

public class Java0610 extends java.applet.Applet{


Expo.drawString(g,"Default Appearance with drawString",20,20); Expo.setFont(g,"Courier",Font.PLAIN,20);Expo.drawString(g,"Courier 20-point plain font",20,60); Expo.setFont(g,"Courier",Font.BOLD,20);Expo.drawString(g,"Courier 20-point bold font",20,100); Expo.setFont(g,"TimesRoman",Font.PLAIN,36);Expo.drawString(g,"Times Roman 36-point plain font",20,180);Expo.setFont(g,"TimesRoman",Font.ITALIC,36);Expo.drawString(g,"Times Roman 36-point italic font",20,260);Expo.setFont(g,"Arial",Font.PLAIN,72);Expo.drawString(g,"Arial 72-point plain font",20,400); Expo.setFont(g,"Algerian", Font.BOLD+Font.ITALIC, 48);Expo.drawString(g,"Algerian 48-point bold/italic font",20,500); Expo.setFont(g,"Qwerty",Font.PLAIN,24);Expo.drawString(g,"Arial 24-point plain font substituted for non-existent Qwerty font",20,600);

}}

// Java0611.java// This program draws a pentagon with the <drawPolygon> method.// The <drawPolygon> method can draw polygon in the range of // [3-12] coordinate points. import java.awt.*;import java.applet.*; public class Java0611 extends Applet{


Expo.drawPolygon(g,500,100,800,200,600,400,400,400,200,200);}

}

500,100

800,200

600,400400,400

200,200

// Java0612.java// This program demonstrates that the sequence of adding coordinate// points as parameters is significant. The same coordinates of the // previous program are used in a different sequence. // The display is very different. import java.awt.*;import java.applet.*; public class Java0612 extends Applet{


Expo.drawPolygon(g,400,400,500,100,800,200,200,200,600,400);}

}

500,100

800,200

600,400400,400

200,200

// Java0613.java// This program demonstrates fillPolygon. import java.awt.*;import java.applet.*; public class Java0613 extends Applet{


Expo.fillPolygon(g,500,100,800,200,600,400,400,400,200,200);}

}

// Java0614.java// This program fills 2 Polygons to draw a little boy with a red shirt // and blue pants.import java.awt.*;import java.applet.*;public class Java0614 extends Applet{


Expo.drawCircle(g,500,100,50);Expo.drawLine(g,500,150,500,400);Expo.drawLine(g,500,400,400,600);Expo.drawLine(g,500,400,600,600);Expo.drawLine(g,300,225,700,225);Expo.setColor(g,Expo.red);Expo.fillPolygon(g,350,200,650,200,650,250,575,250,575,350,425,

350,425,250,350,250);Expo.setColor(g,Expo.blue);Expo.fillPolygon(g,425,375,425,425,350,550,450,600,500,450,550,

600,650,550,575,425,575,375);}

}

// Java0615.java // This program reviews drawPolygon, setFont, and drawString.import java.awt.*;import java.applet.*;public class Java0615 extends Applet{

public void paint(Graphics g) {

Expo.drawPolygon(g,175,175,250,50,350,200);Expo.drawString(g,"Triangle",225,150); Expo.drawPolygon(g,400,200,525,200,600,50,475,50);Expo.setFont(g,"Arial",Font.BOLD,16);Expo.drawString(g,"Quadralateral",425,175);Expo.drawPolygon(g,650,100,750,50,850,100,850,200,650,200);Expo.setFont(g,"Arial",Font.ITALIC,24);Expo.drawString(g,"Pentagon",700,150);Expo.drawPolygon(g,25,250,225,250,175,325,225,400,25,400,75,325);Expo.setFont(g,"TimesRoman",Font.PLAIN,24);Expo.drawString(g,"Hexagon",75,375);Expo.drawPolygon(g,275,250,375,250,475,300,475,400,350,400,350,325,275,325);Expo.setFont(g,"TimesRoman",Font.BOLD,28);Expo.drawString(g,"Heptagon",300,300);

Continued on the next slide…

…Java0615.java Continued

Expo.drawPolygon(g,525,300,600,250,650,250,725,300,725,350,650,400,600,400,525,350);Expo.setFont(g,"TimesRoman",Font.BOLD+Font.ITALIC,44);Expo.drawString(g,"Octagon",550,340);Expo.drawPolygon(g,775,300,800,250,975,250,925,325,975,325,975,400,875,400,825,375,

850,325);Expo.setFont(g,"TimesRoman",Font.ITALIC,36);Expo.drawString(g,"Nonagon",800,300);Expo.drawPolygon(g,150,500,200,450,250,500,300,450,350,500,350,550,300,600,250,550,

200,600,150,550);Expo.setFont(g,"Algerian",Font.PLAIN,36);Expo.drawString(g,"Decagon",175,540);Expo.drawPolygon(g,400,450,600,450,575,525,600,525,600,600,550,575,500,600,450,575,

400,600,400,525,425,525);Expo.setFont(g,"Courier",Font.BOLD,28);Expo.drawString(g,"Undecagon",425,560);Expo.drawPolygon(g,650,525,700,450,700,525,725,525,725,450,775,450,775,525,800,525,

800,450,850,525,850,600,650,600);Expo.setFont(g,"Courier",Font.ITALIC,28); Expo.drawString(g,"Dodecagon",675,560);

}}

The drawRegularPolygon MethodExpo.drawRegularPolygon(g, centerX, centerY, radius, sides);The first 4 parameters for Expo.drawRegularPolygon are the same as Expo.drawCircle.The last parameter indicates the number of sides.

centerX, centerY

radius

// Java0616.java// This program demonstrates the drawRegularPolygon of the Expo class.// Regular Polygons are drawn from their center (X,Y) with a certain // radius and a certain number of sides with// drawRegularPolygon(g,x,y,radius,numSides).

import java.awt.*;import java.applet.*;

public class Java0616 extends Applet{


Expo.drawRegularPolygon(g,200,170,130,5); Expo.drawRegularPolygon(g,500,170,130,6); Expo.drawRegularPolygon(g,800,170,130,7); Expo.drawRegularPolygon(g,200,490,130,8); Expo.drawRegularPolygon(g,500,490,130,9); Expo.drawRegularPolygon(g,800,490,130,10);

}}

// Java0617.java// This program demonstrates fillRegularPolygon.




Expo.setColor(g,Expo.blue);Expo.fillRegularPolygon(g,200,170,130,5); Expo.setColor(g,Expo.gold);Expo.fillRegularPolygon(g,500,170,130,6); Expo.setColor(g,Expo.magenta);Expo.fillRegularPolygon(g,800,170,130,7); Expo.setColor(g,Expo.red);Expo.fillRegularPolygon(g,200,490,130,8); Expo.setColor(g,Expo.green);Expo.fillRegularPolygon(g,500,490,130,9); Expo.setColor(g,Expo.purple);Expo.fillRegularPolygon(g,800,490,130,10);

}}

The drawStar MethodExpo.drawStar(g, centerX, centerY, radius, points);The first 3 parameters for Expo.drawStar are the same as Expo.drawCircle.The last parameter indicates the number of points.

radius

centerX, centerY

// Java0618.java// This program demonstrates the drawStar and fillStar methods.




Expo.setColor(g,Expo.blue);Expo.drawStar(g,200,170,130,5); Expo.setColor(g,Expo.gold);Expo.fillStar(g,500,170,130,6); Expo.setColor(g,Expo.magenta);Expo.drawStar(g,800,170,130,7); Expo.setColor(g,Expo.red);Expo.fillStar(g,200,490,130,8); Expo.setColor(g,Expo.green);Expo.drawStar(g,500,490,130,9); Expo.setColor(g,Expo.purple);Expo.fillStar(g,800,490,130,10);

}}

// Java0619.java// This program demonstrates setColor command being used to "create" // new colors. The program will draw the Official Texas Flag with the // EXACT shades of red and blue.




Expo.setColor(g,0,39,104); // Official shade of blue used in the Texas FlagExpo.fillRectangle(g,0,0,325,650);Expo.setColor(g,190,10,47); // Official shade of red used in the Texas FlagExpo.fillRectangle(g,325,325,1000,650);Expo.setColor(g,255,255,255); Expo.fillStar(g,162,325,130,5);

}}

// Three 255s is the same as color Expo.white

Where do you get the 3 color #sI started by downloading an image of the Official Texas Flag. I then loaded it in Paint.

Using the eye-dropper tool, I then clicked on the desired color.

I then clicked[Edit Colors] and made note of the red, green & blue values.

By using the same 3 numbers in my program, I get the exact same color in the output of my Java program: Expo.setColor(g,0,39,104);

// Java0620.java// This program shows all the shades of Red, Green and Blue using the <setColor> method.import java.awt.*; import java.applet.*;public class Java0620 extends Applet{


int x = 50;for (int red = 0; red <= 255; red++){

Expo.setColor(g,red,0,0);Expo.drawLine(g,x,0,x,650);x++;

}x = 350;for (int green = 0; green <= 255; green++){

Expo.setColor(g,0,green,0);Expo.drawLine(g,x,0,x,650);x++;

}x = 650;for (int blue = 0; blue <= 255;blue++){

Expo.setColor(g,0,0,blue);Expo.drawLine(g,x,0,x,650);x++;

} }

}

// Java0621.java// This program uses the <random> method of the Expo class // 5 times to create 5 random numbers between 1 and 100.



System.out.println("\nJAVA0621.JAVA\n");System.out.println(Expo.random(1,100));System.out.println(Expo.random(1,100));System.out.println(Expo.random(1,100));System.out.println(Expo.random(1,100));System.out.println(Expo.random(1,100));

}}

Since we are working with RANDOM numbers, your outputs will be different than mine – and also

different from the other students in the class.

// Java0622.java// This program allows the user to specify the range of random numbers.



System.out.println("\nJAVA0622.JAVA\n");System.out.print("Enter the smallest number you want. --> ");int minimum = Expo.enterInt();System.out.print("Enter the largest number you want. --> ");int maximum = Expo.enterInt();System.out.println();System.out.println(Expo.random(minimum,maximum));System.out.println(Expo.random(minimum,maximum));System.out.println(Expo.random(minimum,maximum));System.out.println(Expo.random(minimum,maximum));System.out.println(Expo.random(minimum,maximum));System.out.println();

}}

// Java0623.java// This program displays 1000 random lines.




for (int k = 1; k <= 1000; k++){

int x1 = Expo.random(0,1000);int y1 = Expo.random(0,650);int x2 = Expo.random(0,1000);int y2 = Expo.random(0,650);Expo.drawLine(g,x1,y1,x2,y2);

}}

}

Changing Random Number Ranges to Affect the

Graphics Program OutputThe next several slides will still show program Java0623.java, but the output of the program is different. You need to figure out how to change the each program to make it produce the output shown.

NOTE: This skill is essential indoing Graphics Lab 03!





for (int k = 1; k <= 1000; k++){


}}

}

// Java0624.java// This program displays 1000 random colored solid circles.// All circles have a radius of 50.




for (int k = 1; k <= 1000; k++){

int x = Expo.random(0,1000);int y = Expo.random(0,650);int red = Expo.random(0,255);int green = Expo.random(0,255);int blue = Expo.random(0,255);Expo.setColor(g,red,green,blue);Expo.fillCircle(g,x,y,50);

}}

}

// Java0625.java// This program displays 1000 random colored solid circles, with random radii.




for (int k = 1; k <= 1000; k++){

int x = Expo.random(0,1000);int y = Expo.random(0,650);int red = Expo.random(0,255);int green = Expo.random(0,255);int blue = Expo.random(0,255);int radius = Expo.random(1,100);Expo.setColor(g,red,green,blue);Expo.fillCircle(g,x,y,radius);

}}

}

// Java0626.java// This program displays 1000 randomly colored equalateral triangles.// Creating random colors is also simplified with the setRandomColor method.




for (int k = 1; k <= 1000; k++){

int x = Expo.random(0,1000);int y = Expo.random(0,650);int radius = Expo.random(1,100);int sides = 3;Expo.setRandomColor(g);Expo.fillRegularPolygon(g,x,y,radius,sides);

}}

}

// Java0627.java// This program displays 1000 randomly colored polygons with a random # of sides.




for (int k = 1; k <= 1000; k++){

int x = Expo.random(0,1000);int y = Expo.random(0,650);int radius = Expo.random(1,100);int sides = Expo.random(3,10);Expo.setRandomColor(g);Expo.fillRegularPolygon(g,x,y,radius,sides);

}}

}

Using Object

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