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Chapter 6 Slides

Exposure Java 2011 PreAPCS Edition. Chapter 6 Slides. Class Methods & Object Methods. PowerPoint Presentation created by: Mr. John L. M. Schram and Mr. Leon Schram Authors of Exposure Java. Section 6.2. Classes &. Objects. abs. sqrt. max. min. round. pow. ceil. floor.

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Chapter 6 Slides

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  1. Exposure Java 2011 PreAPCS Edition Chapter 6 Slides Class Methods & Object Methods PowerPoint Presentation created by: Mr. John L. M. Schram and Mr. Leon Schram Authors of Exposure Java

  2. Section 6.2 Classes & Objects

  3. abs sqrt max min round pow ceil floor Review ofMath Class Methods

  4. PI E Review of Math Class Attributes

  5. VisualClasses 1 Class: Bug 4 Objects: All Bug Objects

  6. VisualClasses 2 Classes: Bug Flower 7 Objects: 4 Bug Objects 3 Flower Objects

  7. VisualClasses 4 Classes: Bug Flower Rock Actor 4 Objects: 1 Bug Object 1 Flower Object 1 Rock Object 1 Actor Object

  8. Section 6.3 Using Object Methods

  9. // 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(); } }

  10. // Java0602.java // This program creates two Bank objects, called tom and sue. // Each object stores its own Bank information. public class Java0602 { public static void main (String args[]) { 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(); } }

  11. 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;

  12. // 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 { public static void main (String args[]) { 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(); } }

  13. The Preferred Way Let 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);

  14. // 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 { public static void main (String args[]) { 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(); } }

  15. Section 6.4 Using the DecimalFormat class

  16. // 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 public class Java0605 { public static void main (String args[]) { 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(); } } NOTE: The output.format is ignored for numbers that are too large.

  17. // Java0606.java // This program demonstrates how to insert commas in numerical output // with a <DecimalFormat> object. import java.text.DecimalFormat; public class Java0606 { public static void main (String args[]) { 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

  18. // 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; public class Java0607 { public static void main (String args[]) { 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(); } }

  19. // 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 { public static void main (String args[]) { 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(); } }

  20. Section 6.5 Displaying Graphics Characters

  21. // 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); } }

  22. The drawString Method Expo.drawString(g,"Hello There!", x, y); Draws any String starting at coordinate (x,y). Hello There! x, y

  23. // 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 { public void paint(Graphics g) { 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); } }

  24. Section 6.6 Drawing Polygons

  25. // 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 { public void paint(Graphics g) { Expo.drawPolygon(g,500,100,800,200,600,400,400,400,200,200); } } 500,100 800,200 200,200 400,400 600,400

  26. // 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 { public void paint(Graphics g) { Expo.drawPolygon(g,400,400,500,100,800,200,200,200,600,400); } } 500,100 800,200 200,200 400,400 600,400

  27. // Java0613.java // This program demonstrates fillPolygon. import java.awt.*; import java.applet.*; public class Java0613 extends Applet { public void paint(Graphics g) { Expo.fillPolygon(g,500,100,800,200,600,400,400,400,200,200); } }

  28. // 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 { public void paint(Graphics g) { 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); } }

  29. // 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…

  30. …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); } }

  31. Section 6.7 Drawing Regular Polygons

  32. The drawRegularPolygon Method Expo.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

  33. // 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 { public void paint(Graphics g) { 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); } }

  34. // Java0617.java // This program demonstrates fillRegularPolygon. import java.awt.*; import java.applet.*; public class Java0617 extends Applet { public void paint(Graphics g) { 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); } }

  35. The drawStar Method Expo.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. centerX, centerY radius

  36. // Java0618.java // This program demonstrates the drawStar and fillStar methods. import java.awt.*; import java.applet.*; public class Java0618 extends Applet { public void paint(Graphics g) { 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); } }

  37. Section 6.8 Creating new Colors

  38. // 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. import java.awt.*; import java.applet.*; public class Java0619 extends Applet { public void paint(Graphics g) { Expo.setColor(g,0,39,104); // Official shade of blue used in the Texas Flag Expo.fillRectangle(g,0,0,325,650); Expo.setColor(g,190,10,47); // Official shade of red used in the Texas Flag Expo.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

  39. Where do you get the 3 color #s I 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);

  40. // 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 { public void paint(Graphics g) { 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++; } } }

  41. Section 6.9 Creating Random Numbers

  42. // Java0621.java // This program uses the <random> method of the Expo class // 5 times to create 5 random numbers between 1 and 100. public class Java0621 { public static void main (String args[]) { 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)); } }

  43. Java0621 Outputs Since we are working with RANDOM numbers, your outputs will be different than mine – and also different from the other students in the class.

  44. // Java0622.java // This program allows the user to specify the range of random numbers. public class Java0622 { public static void main (String args[]) { 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(); } }

  45. Java0622 Outputs

  46. Section 6.10 Random #s with Graphics

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