CPSC 233, winter 2013 1

Introduction to Computer Science for

Majors II

CPSC 233, Winter 2013

Tutorial 7, Feb 6/7, 2013

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Quiz 2Definitions

OO exercises

Quiz 2

CPSC 233, winter 2013

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DefinitionsAccess modifiers: public vs. private

OO: declaration vs. instantiation

OO: reference vs. object

Variables: scope vs. lifetime

Class members: attributes vs. methods

Information hiding: Mutators vs. accessors

CPSC 233, winter 2013

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Quiz 2Definitions

OO exercises

Quiz 2

CPSC 233, winter 2013

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ExerciseIdentify the class definition, body of methods, attributes, local

variables.

CPSC 233, winter 2013

1. public class Inventory2. {3. private String productName;4. private int productID;5. public int stockLevel;

6. public void setProductInfo (String name, int id, int level)7. {8. productName = name;9. productID = id;10. stockLevel = level;11. }

12. public void getProductInfo ()13. {14. String info = "";15. info += productName + "," + productID + "," + stockLevel;16. return info;17. }18. }

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ExerciseIdentify the scope, in terms of line numbers, of each attribute

and local variable

CPSC 233, winter 2013

1. public class Inventory2. {3. private String productName;4. private int productID;5. public int stockLevel;

6. public void setProductInfo (String name, int id, int level)7. {8. productName = name;9. productID = id;10. stockLevel = level;11. }

12. public void getProductInfo ()13. {14. String info = "";15. info += productName + "," + productID + "," + stockLevel;16. return info;17. }18. }

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ExerciseGiven the Inventory class, identify the invalid statements in

the following Driver class.

CPSC 233, winter 2013

1. public class Driver2. {3. static void main (String[] args)4. {5. Inventory product;6. product.setProductInfo("bread", 3456, 100);7. product = new Inventory();8. product.setProductInfo ("milk", 1234, 50);9. System.out.println(product.productName);10. product.productID = 3425;11. product.stockLevel --;12. product = null;13. System.out.println(product.getProductInfo());14. }15. }

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ExerciseGiven the Driver class, implement the missing methods in

the Inventory class.

CPSC 233, winter 2013

1. public class Driver2. {3. static void main (String[] args)4. {5. Inventory product = new Inventory();6. product.setProductName ("bread");7. product.setProductID (3456);8. product.increaseStock (); // increase stock level by 19. System.out.println(product.getProductInfo());10. product.stockLevel --;11. System.out.println(product.getProductInfo());12. }13. }

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Exercise Given the Inventory class, complete the main() method in the Driver class to do the

following. Instantiates two objects of the Inventory class Update the product info for the 1st object to “coke” with product ID as 1239 and stock level 40 Update the produce info for the 2nd object to “pepsi” with produce ID as 1237 and stock level

39 Increase the stock level for both product using the new method from the previous slide Print the information of both products

CPSC 233, winter 2013

public class Driver{ static void main (String[] args) {

}}

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Quiz 2Definitions

OO exercises

Quiz 2

CPSC 233, winter 2013