Rectangle. Lecture 2 week 2 - Objects & Classes Exercise 1. A. Write a driver class code in java depending on the following UML:

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1 Lecture 2 week 2 - Objects & Classes Exercise 1 A. Write a driver class code in java depending on the following UML: Rectangle - height : double - width : double <<constructor>> Rectangle() <<constructor>> Rectangle ( h : double, w : double) + setheight(h: double) + setwidth(w : double) + getheight(): double + getwidth() : double + areaofrectangle(): double + perimeterofrectangle () : double Each method in the class should do the following: Non- parameterized constructor (Rectangle( ) ) initializes height and width with the value 0 2. parameterized constructor (Rectangle (double h, double w) ) initializes height and width with the h, w respectively. 3. setheight method sets the height instance variable with the value of the parameter h 4. setwidth method sets the width instance variable with the value of the parameter w 5. getheight method returns the height instance variable 6. getwidth method returns the width instance variable 7. areaofrectangle method returns the area of a rectangle area = width * height 8. perimeterofrectangle method return the perimeter of a rectangle perimeter = 2 * (width + height) B. Write a program to test class Rectangle: Create object rectangle1 from the class Rectangle a. b. c. d. For this object call the no- argument constructor then set the width and height using setters methods with 5 and 6 respectively. Print the width and height. Then print the area. Then print the perimeter Of Rectangle. 2. Create object rectangle2 from the class Rectangle a. b. c. d. For this object call the parameterized constructor with the values 4 and 2. Print the width and height. Then print the area. Then print the perimeter Of Rectangle. Lec. Aishah Alhasawi 1 out of 6

2 A: solution lec. Aishah Alhasawi */ public class Rectangle { private double width; private double height; public Rectangle(){ width=0; height=0;} public Rectangle(double h, double w ){ height=h; width=w; } public void setheight(double h){ height=h;} public void setwidth(double w){ width=w;} public double getheight(){ return height;} public double getwidth(){ return w idth;} public double areaofrectangle(){ return w idth*height;} public double perimeterofrectangle (){ return 2*(width+height);} } B: solution public class RectangleTest { /** Lec. Aishah Alhasawi */ public static void main(string[] args) { Rectangle rectangle1=new Rectangle(); rectanglesetwidth(5); rectanglesetheight(6); System.out.printf("Rectangle 1\n w idth= %.2f, height= %.2f",rectanglegetWidth(),rectanglegetHeight()); System.out.printf("\nArea = %.2f",rectangleareaOfRectangle()); System.out.printf("\nPriemeter = %.2f\n",rectangleperimeterOfRectangle()); Rectangle rectangle2=new Rectangle(4,2); System.out.printf("Rectangle 2\n w idth= %.2f, height= %.2f",rectangle2.getWidth(),rectangle2.getHeight()); System.out.printf("\nArea = %.2f",rectangle2.areaOfRectangle()); System.out.printf("\nPriemeter = %.2f",rectangle2.perimeterOfRectangle()); } } Lec. Aishah Alhasawi 2 out of 6

3 Lecture 2+3 week 3 - Objects & Classes Exercise public class Child{ private String name; private int age; private String gender; //female or male public Child(){ name="na"; age=0; gender="famale"; } public void setage(int age){ this.age= ((age>0 && age <=12)?age:1); } public void setname(string name){this.name=name;} public void setgender(string gender){ this.gender=gender; } public int getage(){return this.age;} public String getname(){return name;} public String getgender(){return gender;} 15. public String tostring(){ 16. return String.format("%n++Child Info++%nName: %s%nage:%d%ngender: %s%n",getname(),getage(),getgender());} 17. }//end of class Child public class Mother{ private String name; private int age; private Child childern[ ]; private int counter; public Mother(String name,int age,int numberofchildren){ this.name=name; this.age=age; counter=0; childern=new Child[numberOfChildren]; } public void setage(int age){ this.age=age; } public void setname(string name){this.name=name;} public int getage(){return this.age;} public String getname(){return name;} public void setchildern(child c){childern[counter++]=c;} public void setchildern(string name, int age, String gender){ Child c=new Child(); c.setname(name); c.setage(age); c.setgender(gender); childern[counter++]=c; } public void getchildern(){ for(int i=0;i<childern.length;i++){ System.out.print(childern[i]);} } 26. public String tostring(){ 27. return String.format("==============================%nMother %s, %d old year%n==============================",getname(), getage()); } 28. }//end of class Mother Lec. Aishah Alhasawi 3 out of 6

4 Question A: complete the following questions depending on class Child and Mother. Q1: what is the relationship between class Child and Mother: a. is- relationship b. has- relationship c. no- relationship d. none of the before Q2: How many composition in class Mother? Two composition name object of class String and children object of class Child Q3: How many Constructor in class Mother? One Q4: How many Constructor in class Child? One Q5: The purpose of the constructor is to initialize an object of a class/ to initialize the data members of a class / to initialize the instance variables of a class Q6: What is the type of the constructor in class Mother? a. parameterized constructor b. non- parameterized constructor c. default constructor d. none of the before Q7: What is the type of the constructor in class Child? a. parameterized constructor b. non- parameterized constructor c. default constructor d. none of the before Q8: if we did not declare any constructor in class child, the compiler will call the default constructor. Q9: in class Child, line 9, the value of age is validated/ checked before storing it in the filed age of the class Child. Q10:How can we access the private data (fields) in class Child out side the class? using set and get methods of each field. Q10: draw the UML diagram of relationship between class Child and Mother. Child Mother - name : String - age : int - childern[ ] : Child - counter : int <<constructor>>mother(name :String, age : int, numberofchildren : int) + setage(age : int ) + setname(name : String) + getage() : int + getname() : String +setchildern( c : Child) + setchildern(name : String, age : int, gender : String) + getchildern() + tostring() : String Lec. Aishah Alhasawi - name : String - age : int - gender : String <<constructor>>mother(name :String, age : int, numberofchildren : int) + setage(age : int ) + setname(name : String) + setgender(gender : String) + getage() : int + getname() : String + getgender() : String + tostring() : String 4 out of 6

5 Question B: depending on Child and Mother classes, What is the output of the following code (class Test ) Draw the memory public class Test { public static void main(string[] args) { Child child1=new Child(); Child child2=new Child(); Child child3=new Child(); childsetname("faisl"); childsetage(3); childsetgender("boy"); child2.setname("nourh"); child2.setage(5); child2.setgender("girl"); Mother mother1=new Mother("Sara Essa", 30,3); Mother mother2=new Mother("Amal Ahmed", 25,1); child3.setname("khalid"); child3.setage(2); child3.setgender("boy"); System.out.println(mother1); mothersetchildern(child1); mothersetchildern(child2); mothersetchildern("hanan", 4, "Girl"); mothergetchildern(); 22. System.out.println(mother2); 23. mother2.setchildern(child3); 24. mother2.getchildern(); 25. } 26. } Lec. Aishah Alhasawi 5 out of 6

6 Output: ============================== Mother Sara Essa, 30 old year ============================== ++Child Info++ Name: Faisl age:3 Gender: Boy ++Child Info++ Name: Nourh age:5 Gender: Girl ++Child Info++ Name: Hanan age:4 Gender: Girl ============================== Mother Amal Ahmed, 25 old year ============================== ++Child Info++ Name: Khalid age:2 Gender: Boy Lec. Aishah Alhasawi 6 out of 6