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Signature _____________________ Name ________________________
cs11f ____ Student ID ____________________
CSE 11
Final
Fall 2010
Page 1 ___________ (14 points)
Page 2 ___________ (20 points)
Page 3 ___________ (36 points)
Page 4 ___________ (14 points)
Page 5 ___________ (10 points)
Page 6 ___________ (15 points)
Page 7 ___________ (25 points)
Page 8 ___________ (8 points)
Page 9 ___________ (30 points)
Page 10 ___________ (9 points)
Total ___________ (181 points = 172 base points + 9 points EC [5%])
This exam is to be taken by yourself with closed books, closed notes, no electronic devices.
You are allowed both sides of an 8.5"x11" sheet of paper handwritten by you.
(Partial) Operator Precedence Table
Operators Associativity
! ++ -- (pre & post inc/dec) right to left
* / % left to right
+ - left to right
< <= > >= left to right
== != left to right
&& left to right
|| left to right
= right to left
1) Which of the following are valid Java identifiers? (Circle your answer(s).)
1stJavaClass My-First-Java-Class sEvEnTeEn CSE11Is_1_
C$E11 CSE_11 My1stJavaClass float
2) Using the operator precedence table above, evaluate each expression and state what gets printed. Remember
short-circuit evaluation with && and ||.
int i = 1, j = 2, k = 3, m = 2;
System.out.println( !( k <= m ) ); ________
System.out.println( j <= i && j == m || k <= m ); ________
System.out.println( !(i >= 1) && j != 4 ); ________
System.out.println( !(i > 4 || j <= 6) == i >= 4 && j > 6 ); ________
3) What are the values of the indicated variables after the following code segments are executed?
int a = 2, b = 6;
boolean c = !(b > 4) && (a <= 6) && (a <= 4) || (b > 6);
if ( a++ >= 4 && --b >= 3 )
a = a++ + --b;
else
a = ++a + b--;
a =
b =
c =
int x = 2, y = 6;
boolean z = !((x > 4) || (y <= 6)) == ((y <= 4) && (x > 6));
if ( x++ >= 4 || --y >= 3 )
x = x++ + --y;
else
x = ++x + y--;
x =
y =
z =
7) An interface definition is limited to having only ______________________________ and
________________________________.
A concrete class cannot have ___________________________________ declared in its definition.
A _____________ class cannot have any subclasses.
The keyword to denote inheritance of interface is ______________________.
The keyword to denote inheritance of implementation is ______________________.
8) Complete the following method which is intended to return the sum of all values less than the parameter val
in the array numbers.
public static int sumLessThanVal( int[] numbers, int val ) { int sum = ____________;
for ( int i = _____________; ______________________________________________________; __________ ) { if ( ______________________________________________________ ) { _______________________________________________________ ; } } return ____________; }
9) What is the output produced by the following program? (Hint: draw stack frames)
public class Mystery
public static void main( String[] args )
Mystery ref = new Mystery();
System.out.println( ref.mystery( 8 ) );
public int mystery( int a )
int b = a + 3;
int c = a - 5;
if ( c > 0 )
System.out.println( a + " " + b + " " + c );
c = b + mystery( --a );
System.out.println( a + " " + b + " " + c );
else
c = a + b;
System.out.println( "Stop!" );
System.out.println( a + " " + b + " " + c );
return c;
Output
10) Given the following definition of class Thing1, what is the output of the Java application Question10?
class Thing { private int count;
public Thing1( int count ) { this.count = count; }
public int getCount() { return this.count; }
public void setCount( int count ) { this.count = count; }
public String toString() { if ( this.count == 5 ) return "five"; else if ( this.count == 6 ) return "six"; else if ( this.count == 7 ) return "seven"; else return "need more"; }
public void swap1( Thing1 t2 ) { Thing1 temp; Thing1 t1 = this;
temp = t1; t1 = t2; t2 = temp; }
public void swap2( Thing1 t2 ) { int temp;
temp = this.getCount(); this.setCount( t2.getCount() ); t2.setCount( temp ); } }
public class Question { public static void main( String[] args ) { Thing1 first = new Thing1( 7 ); Thing1 second = new Thing1( 5 );
Thing1 temp = first; first = second; second = temp;
System.out.println( first.toString() ); System.out.println( second.toString() );
Thing1 third = new Thing1( 5 ); Thing1 fourth = new Thing1( 4 );;
third.swap2( fourth );
System.out.println( third.toString() ); System.out.println( fourth.toString() );
first.setCount( third.getCount() ); fourth = second;
System.out.println( first == third ); System.out.println( second == fourth ); System.out.println( first.toString().equals( third.toString() ) ); System.out.println( second.toString().equals( fourth.toString() ) );
System.out.println( first.toString() ); System.out.println( second.toString() ); System.out.println( third.toString() ); System.out.println( fourth.toString() );
first = new Thing1( 6 ); second = new Thing1( 4 );
first.swap1( second );
System.out.println( first.toString() ); System.out.println( second.toString() ); } }
Output
____________
____________
____________
____________
____________
____________
____________
____________
____________
____________
____________
____________
____________
____________
13) Given the following definitions:
And the following variable definitions:
Puppy puppy; Kitty kitty; MyPet pet;
Indicate which are valid Java statements. Consider each statement executed sequentially in the order it appears.
A) Invalid Java statement – Compiler Error
B) Valid Java statement – No Compiler Error
kitty = new Kitty(); _______
puppy = new Puppy(); _______
pet = kitty; _______
pet.speak(); _______
pet.wag(); _______
pet.sleep( 3000 ); _______
kitty = pet; _______
pet = new MyPet(); _______
pet = puppy; _______
pet.speak(); _______
( (Puppy) pet).wag(); _______
( (Puppy) pet).sleep( 3000 ); _______
puppy = pet; _______
puppy = kitty; _______
kitty.wag(); _______
public abstract class MyPet { public abstract String speak(); }
public class Puppy extends MyPet { private static final String PUPPY_SPEAK = "Bark";
public Puppy() { // ctor initialization here }
public String speak() { return PUPPY_SPEAK; }
public void sleep( int time ) { // puppy sleeps for time seconds } }
public class Kitty extends MyPet { private static final String KITTY_SPEAK = "Meow";
public Kitty() { // ctor initialization here }
public String speak() { return KITTY_SPEAK; }
public void wag() { // kitty wags its tail } }
Hint: What does the compiler know about
any reference variable at compile time (vs.
run time)?
14) Given the following class definitions:
abstract class Animal { private String name; public Animal() { this( "Animal" ); } public Animal( String name ) { this.name = name; } public String toString() { return name; } public abstract String speak(); }
class Cat extends Animal { public Cat() {} public Cat( String name ) { super( name + " Cat" ); } public String speak() { return "Meow"; } }
class Tiger extends Cat { public Tiger() { this( "Ko Ko" ); }; public Tiger( String name ) { super( name + " Tiger" ); } public String speak( String name ) { return name + " Roar"; } }
class BigTiger extends Tiger { public BigTiger() { super( "Anu Tiger" ); } public BigTiger( String name ) { super( name ); } public String speak() { return super.speak( "Anu" ); } }
class Lion extends Cat { public String speak() { return "Heather Lion " + super.speak(); } public String softer() { return "Bruce Lion " + super.speak(); } }
public class Test14 { public static void main( String[] args ) {
Animal a;
a = new Lion(); System.out.println( a + " says " + a.speak() );
a = new BigTiger( "Ankur" ); System.out.println( a + " says " + a.speak() );
a = new Cat( "Brina" ); System.out.println( a + " says " + a.speak() );
a = new Tiger(); System.out.println( a + " says " + a.speak() );
a = new Lion(); System.out.println( a + " says " + ((Lion) a).softer() );
} }
What gets printed when this program is run?
Output
Test16.a = ________
this.b = ________
this.c = ________
c = ________
b = ________
a = ________
Test16.a = ________
this.b = ________
this.c = ________
a = ________
b = ________
c = ________
result = ________
Test16.a = ________
this.b = ________
this.c = ________
a = ________
b = ________
c = ________
x = ________
Use the letters below to identify various program parts.
A) instance variable F) formal parameter
B) class definition (type) G) instance method
C) local variable H) static variable
D) static method I) constructor
E) actual argument
_____ Test16() on line 11 _____ a on line 38
_____ method2() on line 36 _____ c on line 5
_____ Test16 on line 1 _____ a on line 3
_____ ref.c on line 9 _____ x on line 15
_____ main() on line 6 _____ ref on line 8
16) What output is produced by the following program?
1 public class Test 2 { 3 private static int a; 4 private int b; 5 private int c;
6 public static void main( String[] args ) 7 { 8 Test16 ref = new Test16( 5 );
9 ref.method1( ref.c ); 10 }
11 public Test16( int c ) 12 { 13 this.c = c; 14 }
15 public void method1( int x ) 16 { 17 int c = ++x; 18 int b;
19 b = c + 3; 20 a = b + 2;
21 System.out.println( "Test16.a = " + Test16.a ); 22 System.out.println( "this.b = " + this.b ); 23 System.out.println( "this.c = " + this.c ); 24 System.out.println( "c = " + c ); 25 System.out.println( "b = " + b ); 26 System.out.println( "a = " + a ); 27 System.out.println( "result = " + method2( c + b ) ); 28 System.out.println( "Test16.a = " + Test16.a ); 29 System.out.println( "this.b = " + this.b ); 30 System.out.println( "this.c = " + this.c ); 31 System.out.println( "a = " + a ); 32 System.out.println( "b = " + b ); 33 System.out.println( "c = " + c ); 34 System.out.println( "x = " + x ); 35 }
36 private int method2( int x ) 37 { 38 int a = x; 39 int c = this.c + Test16.a;
40 x = b = a + c;
41 System.out.println( "Test16.a = " + Test16.a ); 42 System.out.println( "this.b = " + this.b ); 43 System.out.println( "this.c = " + this.c ); 44 System.out.println( "a = " + a ); 45 System.out.println( "b = " + b ); 46 System.out.println( "c = " + c );
47 Test16.a = a + 2; 48 this.b = b + c;
49 return x + 5; 50 } 51 }
Given the following class definitions for class Foo, class Fubar, and class FubarTest:
public class Foo { public Foo( int x, int y ) { this(); System.out.println( "Foo ctor #1" ); }
public Foo() { System.out.println( "Foo ctor #2" ); }
public String toString() { System.out.println( "Foo.toString" ); return "Foo.toString"; } }
public class Fubar1 extends Foo { public Fubar1( int x, int y, int z ) { super( x, y ); System.out.println( "Fubar ctor #1" ); }
public Fubar1( int x, int y ) { this( x, y, -99 ); System.out.println( "Fubar ctor #2" ); }
public String toString() { System.out.println( "Fubar.toString" ); return super.toString() + " + " + "Fubar.toString"; } }
public class FubarTest { public static void main( String[] args ) { Foo ref = new Fubar1( 25, 151 );
System.out.println( "-----" );
System.out.println( ref.toString() ); } }
17) What is the output when we run FubarTest as in
java FubarTest
Scratch Paper
