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Signature _____________________ Name ________________________
cs11f ____ Student ID ____________________
CSE 11
Midterm
Fall 2012
Page 1 ___________ (20 points)
Page 2 ___________ (17 points)
Page 3 ___________ (31 points)
Page 4 ___________ (15 points)
Page 5 ___________ (8 points)
Page 6 ___________ (20 points)
Total ___________ (111 points = 105 base points + 6 points EC [>5%])
(105 points = 100%)
This exam is to be taken by yourself with closed books, closed notes, no electronic devices.
You are allowed one side 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) What are the values of the indicated variables after the following code segments are executed?
What gets printed?
public class While
public static void main( String[] args )
final int MAX = 10, MIN = 5;
int i = 7, j = 7;
while ( i < MAX )
while ( j >= MIN )
++j;
System.out.println( i + " " + j );
j -= 4; // j = j - 4;
i++;
j = i;
System.out.println( i + " " + j );
int x = 4, y = 6, z;
boolean bool1 = !((x > 4) || (y <= 6)) == ((y <= 4) && !(x > 6));
if ( x++ >= 4 || --y <= 3 )
z = x++ + --y;
else
z = ++x + y--;
int a = 4, b = 6, c;
boolean bool2 = !(b > 4) && (a <= 6) && (a <= 4) || (b > 6);
if ( a++ >= 4 && --b <= 3 )
c = a++ + --b;
else
c = ++a + b--;
bool1 =
x =
y =
z =
bool2 =
a =
b =
c =
Output
this.a = ________
Test3.b = ________
this.c = ________
c = ________
b = ________
a = ________
this.a = ________
Test3.b = ________
this.c = ________
x = ________
a = ________
b = ________
c = ________
result = ________
this.a = ________
Test3.b = ________
this.c = ________
x = ________
a = ________
b = ________
c = ________
Use the numbers below to identify various program parts.
1) local variable 6) static variable
2) instance variable 7) formal parameter
3) static method 8) constructor
4) class definition (type) 9) instance method
5) actual argument
_____ main() on line 6 _____ x on line 40
_____ Test3 on line 1 _____ b on line 4
_____ method2() on line 36 _____ c on line 39
_____ Test3() on line 11 _____ c on line 5
_____ ref.a on line 9 _____ c on line 11
3) What output is produced by the following program?
1 public class Test 2 { 3 private int a; 4 private static int b = 2; 5 private int c;
6 public static void main( String[] args ) 7 { 8 Test3 ref = new Test3( 4 );
9 ref.method1( ref.a ); 10 }
11 public Test3( int c ) 12 { 13 this.c = c; 14 }
15 private void method1( int x ) 16 { 17 int c = x--; 18 int b;
19 b = a + 2; 20 a = c + 3;
21 System.out.println( "this.a = " + this.a ); 22 System.out.println( "Test3.b = " + Test3.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( b + c ) ); 28 System.out.println( "this.a = " + this.a ); 29 System.out.println( "Test3.b = " + Test3.b ); 30 System.out.println( "this.c = " + this.c ); 31 System.out.println( "x = " + x ); 32 System.out.println( "a = " + a ); 33 System.out.println( "b = " + b ); 34 System.out.println( "c = " + c ); 35 }
36 public int method2( int x ) 37 { 38 int b = x; 39 int c = this.c + Test3.b;
40 x = a = b + c;
41 System.out.println( "this.a = " + this.a ); 42 System.out.println( "Test3.b = " + Test3.b ); 43 System.out.println( "this.c = " + this.c ); 44 System.out.println( "x = " + x ); 45 System.out.println( "a = " + a ); 46 System.out.println( "b = " + b ); 47 System.out.println( "c = " + c );
48 Test3.b = b + 2; 49 this.c = a + c;
50 return x + 5; 51 } 52 }
What is the output of this recursive method if it is invoked as ref.mystery( 8 );? Draw Stack Frames to
help you answer this question.
int mystery( int a )
int b = a + 2;
if ( b <= 11 )
System.out.println( a + " " + b );
a = b + mystery( b - 1 );
else
System.out.println( "Whoa" );
b = a - 2;
System.out.println( a + " " + b );
return a - b;
Output
What gets printed by the following code? _______
int x = 12; if ( x < 7 ) { x += 3; // Same as x = x + 3; } else if ( x <= 10 ) { x += 6; } System.out.println( x );
What gets printed by the following code? _______
int x = 12; if ( x > 7 ) { x += 2; // Same as x = x + 2; } else if ( x >= 10 ) { 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 { 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 { x += 6; } System.out.println( x );
6) Trace the following program and specify its output.
public class Trace { public static void main( String[] args ) { foo1(); System.out.println( "main1" ); foo2(); System.out.println( "main2" ); foo3(); System.out.println( "main3" ); foo2(); }
public static void foo1() { foo2(); System.out.println( "A" ); }
public static void foo2() { System.out.println( "B" ); foo3(); System.out.println( "C" ); }
public static void foo3() { System.out.println( "D" ); }
}
What is the default initial value of a local variable that is defined as an int? _________________
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? ____________
Will the following code compile? ___________
If not, what change do you need to make to the method header (not the method body) so that it will compile?
Explain. Be specific.
public boolean test( int x )
System.out.println( "In test" );
return x * x;
Scratch Paper
