A+ Computer Science Inheritance Quiz A

Which reserved word is used to indicate that one class is a child or descendant of another class?

• super

• extends

• implements

• derives

• child

Consider the classes and client code below to determine what is printed by the client code. public class N { private int one; public N() { one=5; } public String toString() { return ""+ one; } } public class O extends N { } //client code N it = new O(); System.out.println( it );

• null

• 0

• 5

• O

• N

Consider the classes and client code below to determine the output of the client code. public class N { private int one; public N( int x ){ one=x; } public String toString(){ return ""+ one; } } public class O extends N { public O( int x ){ super( x ); } } //client code N it = new O(7); System.out.println( it ); a. null b. 0 c. 5 d. 3 e. 7 Answer: e. 7

• null

• 0

• 5

• 3

• 7

Consider the classes below and determine what is printed out by the client code. public class V { public void one(){ System.out.print("it"); } public void two(){ System.out.print("go"); } } public class W extends V { public void one(){ System.out.print("up"); } public void two(){ System.out.print("at"); } public void testIt(){ one(); super.two(); } } /////////////////////////////////////////// //client code in the main of another class V x = new V(); x.one();

• it

• at

• go

• up

• null

Consider the classes below and determine what is printed out by the client code. public class V { public void one(){ System.out.print("it"); } public void two(){ System.out.print("go"); } } public class W extends V { public void one(){ System.out.print("up"); } public void two(){ System.out.print("at"); } public void testIt(){ one(); super.two(); } } /////////////////////////////////////////////// //client code in the main of another class V x = new W(); x.one();

• it

• at

• go

• up

• null

Consider the classes below and determine what is printed out by the client code. public class V { public void one(){ System.out.print("it"); } public void two(){ System.out.print("go"); } } public class W extends V { public void one(){ System.out.print("up"); } public void two(){ System.out.print("at"); } public void testIt(){ one(); super.two(); } } /////////////////////////////////////////// //client code in the main of another class V x = new W(); x.one(); x.two(); a. itgo b. upat c. itat d. upgo e. null Answer: c. itat

• a. itgo

• b. upat

• c. itat

• d. upgo

• e. null

Consider the classes below and determine what is printed out by the client code. public class V { public void one(){ System.out.print("it"); } public void two(){ System.out.print("go"); } } public class W extends V { public void one(){ System.out.print("up"); } public void two(){ System.out.print("at"); } public void testIt(){ one(); super.two(); } } /////////////////////////////////////////////// //client code in the main of another class V x = new W(); x.one(); x = new V(); x.two(); a. itgo b. upat c. itat d. upgo e. null Answer: a. itgo

• a. itgo

• b. upat

• c. itat

• d. upgo

• e. null

Consider the classes below and determine what is printed out by the client code. public class V { public void one(){ System.out.print("it"); } public void two(){ System.out.print("go"); } public void testIt(){ one(); } } public class W extends V { public void one(){ System.out.print("up"); } public void two(){ System.out.print("at"); } public void testIt(){ one(); super.testIt(); super.one(); } } /////////////////////////////////////////////// //client code in the main of another class W x = new W(); x.testIt(); a. itgoup b. upitit c. upupit d. upupup e. null Answer: b. upitit

• itgoup

• upitit

• upupit

• upupup

• null

What is the output by the code below?

• 7 4 4

• 7 2 2

• 4 4

• 2 2

• null

What is the output by the code below?

• 7 4 4

• 7 2 2

• 4 4

• 2 2

• null