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Student ID ____________________ Name ________________________
cs8f ____ Signature _____________________
CSE 8A
Final
Fall 2010
Page 1 ___________ (10 points)
Page 2 ___________ (9 points)
Page 3 ___________ (7 points)
Page 4 ___________ (12 points)
Page 5 ___________ (12 points)
Page 6 ___________ (11 points)
Page 7 ___________ (14 points)
Page 8 ___________ (14 points)
Page 9 ___________ (10 points)
Total ___________ (99 points = 94 base points + 5 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
What gets printed?
public class F { public static void main( String[] args ) { System.out.println( -1 + 2 - 3 * 10 % 4 ); _________
System.out.println( 2 * 7 - 11 / 9 + 10 ); _________ } }
What gets printed?
public class F { public static void main( String[] args ) { int fire = 10, air = 2;
fire = fire * (air + 5); System.out.println( "fire = " + fire ); ________________________
fire = 5 โ air--; System.out.println( "fire = " + fire + "; air = " + air );________________________
fire = 5; air = ++fire + 4; System.out.println( "fire = " + fire + "; air = " + air );________________________ } }
What is printed by the following code?
int foo = 42; int bar = 42; boolean foobar = ( foo == bar ); System.out.println( foobar ); ____________ foo = 37; System.out.println( foobar ); ____________
System.out.println( foo == bar ); ____________
In the code for drawSquare( int size ) discussed in class, we used lines like
this.forward( size );
If drawSquare() is invoked as
koko.drawSquare( 42 );
what does this refer to? (Circle the correct answer.)
What does the following code do? Give a high level answer in plain English words. Assume this method is
stored in the file Picture.java
public void fubar() { Pixel[] pixelArray = this.getPixels();
for ( Pixel p : pixelArray ) { p.setRed( 255 ); p.setGreen( 255 ); p.setBlue( 255 ); } }
Which of the following correctly swaps two values a and b? Write the letter of the correct code here: ______
A B C
D E F
Which of the following are not valid Java identifiers? (Circle your answer(s).)
[+1 โ correct; -1 โ incorrect; No negative score]
this&that thisRthat This_2_That integer
nine2five n!ne_2_5 9_2_5 int
a = b tmp = a b = tmp;
tmp = a b = tmp; a = b
tmp = a b = a b = tmp;
tmp = a b = a a = tmp;
tmp = a a = b b = tmp;
tmp = b a = b b = tmp;
A) this shape
B) this square
C) the object referenced by koko
D) this size
Fill in the blanks below so the code correctly gets the height of a Picture object referenced by a variable named
var1 and stores it in the variable named var2. Be sure to fill in the correct type of variable var2.
Picture var1 = new Picture();
_________ var2; // Fill in the type variable var2 should be defined as.
var2 = _______________________ ; // Fill in the right side of this assignment stmt // to get the height of the Picture object var // references.
The following is a for loop. Write the equivalent as a while loop.
int i; for ( i = 0; i < 42; ++i ) { System.out.println( i * i );
}
Which of the following are instance methods? Circle your answers. (+1 if correct; -1 if incorrect. No neg. pts.)
pictureObj.show(); Math.abs( -3 ); turtle1.turnLeft();
FileChooser.pickAFile(); soundObj.play(); ColorChooser.pickAColor();
Assume there is an array properly defined and a variable named abc references this array.
Write the expression to access the first element in this array? __________________________________
Write the expression to access the last element in this array? __________________________________
What order are pixels changed given this code in Picture.java (assuming all variables are correctly defined and
set)? Write the letter of the correct order here: ______
int width = โฆ ; int height = โฆ ; Pixel p; for ( int j = 0; j < height; j++ ) { for ( int i = 0; i < width; i++ ) { p = getPixel( i, j ); p.setColor( Color.Black ); } }
A) L->R;Top->Down B) L->R;Bottom->Up
C) Bottom->Up;L->R D) Top->Down;L->R
The following method mirrors a Picture vertically left to right. this is a Picture that we are applying the
mirroring.
public void mirrorVertically() { int mirrorPoint = this.getWidth() / 2; Pixel leftPixel = null; Pixel rightPixel = null; Pixel mirrorPixel = null;
for ( int y = 0; y < this.getHeight(); ++y ) { for ( int x = 0; x < mirrorPoint; ++x ) { leftPixel = this.getPixel( x, y ); rightPixel = this.getPixel( this.getWidth() - 1 โ x, y ); mirrorPixel = this.getPixel( mirrorPoint, y ); / MISSING LINE / } } }
Which missing line of code will correctly mirror this Picture vertically left to right? _______
A) mirrorPixel.setColor( leftPixel.getColor() );
B) mirrorPixel.setColor( rightPixel.getColor() );
C) rightPixel.setColor( leftPixel.getColor() );
D) leftPixel.setColor( rightPixel.getColor() );
E) rightPixel.setColor( mirrorPixel.getColor() );
F) leftPixel.setColor( mirrorPixel.getColor() );
Method overloading allows for more than one method with the same _________ as long as the _____________
are different.
What will be output from the following code:
int x = 4; int y = 2;
while ( x < 10 && y <= 3 ) { System.out.println( x + " " + y ); x++; y++; }
System.out.println( x + " " + y );
What gets printed by the following code? _______
int x = 12; if ( x > 7 ) { x += 3; // Same as x = x + 3; } if ( x >= 15 ) { x += 6; } System.out.println( x );
What gets printed by the following code? _______
int x = 12; if ( x > 7 ) { x += 3; // Same as x = x + 3; } else if ( x >= 15 ) { x += 6; } System.out.println( x );
What will be output from the following code:
int x = 2; int y = 0;
while ( x < 5 || y <= 1 ) { x++; y++; System.out.println( x + " " + y ); }
System.out.println( x + " " + y );
Which of the following loops will not cause an ArrayIndexOutOfBounds exception? Circle all the correct
answers. There may be more than one correct answer. [Correct +1; Incorrect: -1; No negative score]
A) for ( int i = 0; i <= this.getWidth(); i++ )
B) for ( int i = this.getWidth(); i > 0; i-- )
C) for ( int i = this.getWidth() โ 1; i >= 0; i-- )
D) for ( int i = 8; i < this.getWidth(); i++ )
E) for ( int i = this.getWidth() โ 8; i > 0; i-- )
F) for ( int i = -1; i < this.getWidth(); i++ )
Given the following code:
public void guess() { int array[] = { 20, 50, 30, 20, 100, 0, 40, 0 };
int a = 200; int b = 0;
for ( int i = 0; i < array.length; i++ ) { int foo = array[i];
if ( foo < a ) { a = foo; b = i; } } System.out.println( a + "," + b ); }
What gets printed? _______________
What is printed if the line if ( foo < a ) was changed to if ( foo > a )? _____________
What is printed if the line if ( foo < a ) was changed to if ( foo <= a )? _____________
What gets printed?
public class F { public static void main( String[] args ) { int x = 5; int y = 8;
System.out.println( false || (y >= 8) ); System.out.println( ++x < y ); System.out.println( true && !(x <= y) ); System.out.println( 4 + x < y ); } }
What is the default initial value of a local variable? _________________
What is the default initial value of an instance variable that is defined as a boolean? ____________
What is the default initial value of an instance variable that is defined as an object reference? ____________
What is the default initial value of an instance variable that is defined as a double? ____________
What gets printed if the value of the actual
argument passed to this method is 0? ________
public void f6( int x ) { int y = 0;
if ( x <= 1 ) y = 3; if ( x <= 2 ) y = 5; if ( x == 3 || x >= 4 ) y = 7; else y = 9;
System.out.println( y ); }
What gets printed if the value of the actual
argument passed to this method is 0? ________
public void f6( int x ) { int y = 0;
if ( x <= 1 ) y = 3; else if ( x <= 2 ) y = 5; else if ( x == 3 || x >= 4 ) y = 7; else y = 9;
System.out.println( y ); }
Scratch Paper
