cs 61b midterm review
DESCRIPTION
CS 61B Midterm Review. HKN, Fall 2010. Predict the output. 1. What is the output of the following code: System.out.println ("ABCDEF".substring(0, 4).substring (1, 3)); Option A: Error Option B: BCD Option C: CD Option D: BC. Predict the output. - PowerPoint PPT PresentationTRANSCRIPT
CS 61B Midterm Review
HKN, Fall 2010
Predict the output
1. What is the output of the following code:System.out.println ("ABCDEF".substring(0, 4).substring (1, 3));
Option A: Error
Option B: BCD
Option C: CD
Option D: BC
Predict the output
1. What is the output of the following code:System.out.println ("ABCDEF".substring(0, 4).substring (1, 3));
Option A: Error
Option B: BCD
Option C: CD
Option D: BC
• “ABCDEF”.substring(0, 4) is the string “ABCD”
• “ABCD”.substring(1, 3) is the string “BC”
Option A: Error
Option B: i= 0
Option C: i= 5
Option D: i = 25
Option A: Error
Option B: i= 0
Option C: i= 5
Option D: i = 25
Option A: Error
Option B: s =
Option C: s = A
Option D: s = AA
Option A: Error
Option B: s =
Option C: s = A
Option D: s = AA
Option A: Error
Option B: true
Option C: false
Option D: Buh?
Option A: Error
Option B: true
Option C: false
Option D: Buh?
Option A: Error
Option B: true
Option C: false
Option D: Buh?
Option A: Error
Option B: true
Option C: false
Option D: Buh?
Option A: Error
Option B: true
Option C: false
Option D: Buh?
Option A: Error
Option B: true
Option C: false
Option D: Buh?
Option A: Error
Option B: 5
Option C: 7
Option D: 10
Option A: Error
Option B: 5
Option C: 7
Option D: 10
Option A: Error
Option B: 5
Option C: 7
Option D: 10
Option A: Error
Option B: 5
Option C: 7
Option D: 10
Option A: Error
Option B: 5
Option C: 7
Option D: 10
Option A: Error
Option B: 5
Option C: 7
Option D: 10
Option A: Error
Option B: True
Option C: False
Option D: ???
Option A: Error
Option B: True
Option C: False
Option D: ???
Option A: Does not compile
Option B: Run time error
Option C: Works
Option D: Don’t know
Dog is a subclass of Animal
Animal a = new Animal();
Dog d = (Dog) a;
Option A: Does not compile
Option B: Run time error
Option C: Works
Option D: Don’t know
Dog is a subclass of Animal
Animal a = new Animal();
Dog d = (Dog) a;
Option A: Does not compile
Option B: Run time error
Option C: Works
Option D: Don’t know
Dog is a subclass of Animal
Animal a = new Dog();
Dog d = (Animal) a;
Option A: Does not compile
Option B: Run time error
Option C: Works
Option D: Don’t know
Dog is a subclass of Animal
Animal a = new Dog();
Dog d = (Animal) a;
Option A: Does not compile
Option B: Run time error
Option C: Works
Option D: Don’t know
Dog is a subclass of Animal
Animal a = new Dog();
Dog d = (Dog) a;
Option A: Does not compile
Option B: Run time error
Option C: Works
Option D: Don’t know
Dog is a subclass of Animal
Animal a = new Dog();
Dog d = (Dog) a;
Option A: Does not compile
Option B: Run time error
Option C: Works
Option D: Don’t know
Dog is a subclass of Animal
Animal[] aa = new Dog[2];
Option A: Does not compile
Option B: Run time error
Option C: Works
Option D: Don’t know
Dog is a subclass of Animal
Animal[] aa = new Dog[2];
Option A: Does not compile
Option B: Run time error
Option C: Calls Dog’s eat method
Option D: Calls Animal’s eat method
Dog is a subclass of Animal BOTH implement :eat(String food)
Dog d = new Dog();
((Animal) d).eat(“kibble”);
Option A: Does not compile
Option B: Run time error
Option C: Calls Dog’s eat method
Option D: Calls Animal’s eat method
Dog is a subclass of Animal BOTH implement :eat(String food)
Dog d = new Dog();
((Animal) d).eat(“kibble”);
Option A: Does not compile
Option B: Run time error
Option C: Works
Option D: Don’t know
Dog is a subclass of AnimalAnimal[] aa = new Animal[2];
aa[0] = new Dog();
aa[1] = new Dog();
Dog[] da = (Dog []) aa;
Option A: Does not compile
Option B: Run time error
Option C: Works
Option D: Don’t know
Dog is a subclass of AnimalAnimal[] aa = new Animal[2];
aa[0] = new Dog();
aa[1] = new Dog();
Dog[] da = (Dog []) aa;
Option A: Does not compile
Option B: Run time error
Option C: Works
Option D: Don’t know
Dog is a subclass of AnimalAnimal[] aa = new Dog[2];Dog [] da = (Dog []) aa;
Option A: Does not compile
Option B: Run time error
Option C: Works
Option D: Don’t know
Dog is a subclass of AnimalAnimal[] aa = new Dog[2];Dog [] da = (Dog []) aa;
Try this at home!
Fill in the blanks below with all possible combinations (there are 16) of Animal and Dog, and determine whether the code will compile, or whether it will produce a compile-time or a run-time error:
______ a = new _____();
______ d = (_____) a;
The moveToEnd method moves the first node of a doubly-linked list to the end of the list. Fill in the blanks:
public class DList {
protected DListNode head;
protected DListNode tail;
public void moveToEnd() {
// Moves the first node of the list to the end
if(head != null) {
tail.next = __________
head.prev = __________
tail = __________
head = __________
tail.next = null;
head.prev = null;
}
}
The moveToEnd method moves the first node of a doubly-linked list to the end of the list. Fill in the blanks:
public class DList {
protected DListNode head;
protected DListNode tail;
public void moveToEnd() {
// Moves the first node of the list to the end
if(head != null) {
tail.next = head;
head.prev = __________
tail = __________
head = __________
tail.next = null;
head.prev = null;
}
}
The moveToEnd method moves the first node of a doubly-linked list to the end of the list. Fill in the blanks:
public class DList {
protected DListNode head;
protected DListNode tail;
public void moveToEnd() {
// Moves the first node of the list to the end
if(head != null) {
tail.next = head;
head.prev = tail;
tail = __________
head = __________
tail.next = null;
head.prev = null;
}
}
The moveToEnd method moves the first node of a doubly-linked list to the end of the list. Fill in the blanks:
public class DList {
protected DListNode head;
protected DListNode tail;
public void moveToEnd() {
// Moves the first node of the list to the end
if(head != null) {
tail.next = head;
head.prev = tail;
tail = head; // equivalently: tail = tail.next;
head = __________
tail.next = null;
head.prev = null;
}
}
The moveToEnd method moves the first node of a doubly-linked list to the end of the list. Fill in the blanks:
public class DList {
protected DListNode head;
protected DListNode tail;
public void moveToEnd() {
// Moves the first node of the list to the end
if(head != null) {
tail.next = head;
head.prev = tail;
tail = head;
head = head.next;
tail.next = null;
head.prev = null;
}
}
Consider the following class definitions:
For each of the main methods below, determine whether the method will cause a compiler error, a run-time error, or if it runs fine, determine what the method will print out
public static void main(String[] argv) { Fuzzy f; Puppy p; f = new Fuzzy(); p = (Puppy) f; System.out.println(p.cuteness());}
Consider the following class definitions:
For each of the main methods below, determine whether the method will cause a compiler error, a run-time error, or if it runs fine, determine what the method will print out
public static void main(String[] argv) { Fuzzy f; Puppy p; f = new Fuzzy(); p = (Puppy) f; System.out.println(p.cuteness());}
Run-time Error:p = (Puppy) f;
Consider the following class definitions:
For each of the main methods below, determine whether the method will cause a compiler error, a run-time error, or if it runs fine, determine what the method will print out
public static void main(String[] argv) { Fuzzy f; Puppy p; p = new Puppy(3); f = p; p = (Puppy) f; System.out.println(f.cuteness());}
Consider the following class definitions:
For each of the main methods below, determine whether the method will cause a compiler error, a run-time error, or if it runs fine, determine what the method will print out
public static void main(String[] argv) { Fuzzy f; Puppy p; p = new Puppy(3); f = p; p = (Puppy) f; System.out.println(f.cuteness());}
Works =)// output:4
Consider the following class definitions:
For each of the main methods below, determine whether the method will cause a compiler error, a run-time error, or if it runs fine, determine what the method will print out
public static void main(String[] argv) { Cute c; Fuzzy f; Puppy p; p = new Puppy(3); f = (Fuzzy) p; c = f; System.out.println(c.cuteness());}
Consider the following class definitions:
For each of the main methods below, determine whether the method will cause a compiler error, a run-time error, or if it runs fine, determine what the method will print out
public static void main(String[] argv) { Cute c; Fuzzy f; Puppy p; p = new Puppy(3); f = (Fuzzy) p; c = f; System.out.println(c.cuteness());}
Compiler Error:c = f;
Consider the following class definitions:
For each of the main methods below, determine whether the method will cause a compiler error, a run-time error, or if it runs fine, determine what the method will print out
public static void main(String[] argv) { Cute c; Fuzzy f; f = new Puppy(3); c = (Cute) f; System.out.println(c.cuteness());}
Consider the following class definitions:
For each of the main methods below, determine whether the method will cause a compiler error, a run-time error, or if it runs fine, determine what the method will print out
public static void main(String[] argv) { Cute c; Fuzzy f; f = new Puppy(3); c = (Cute) f; System.out.println(c.cuteness());}
Works =)// output:4