CSCI A201/A597 and I210

Midterm Exam One

Spring Semester 2002

Directions:

Good luck and do well!

Write your name or username here:______________________

1. What is the output produced by the following three lines (when embedded in a complete program)? 
int x, y;
x = 2; y = 3; 
System.out.println(1 + "x" + y);
  1.   123
  2.   33
  3.   13
  4.   15
  5. other

Note: To save space I wrote other where I would have put "None of the above."

The program prints 1x3 so the correct answer is other.

2. What is the output produced by the following three lines (when embedded in a complete program)? 
int x, y;
x = 3; y = 2; 
System.out.println("1" + (x + y));
  1.   132
  2.   33
  3.   13
  4. 15
  5.   6
3. What is the output produced by the following two lines (when embedded in a complete program)? 
char a; a = 3 + 'B'; 
System.out.println(a);
  1. E
  2.   B
  3.   C
  4.   3
  5.   other
4. What is the output produced by the following program fragment (when embedded in a complete program)? Note that the indentation may or may not be right so please be careful. 
if ('C' < 'A' + 3) 
  System.out.print(1 + 3 / 2); 
  System.out.print(2);
  1.   2
  2.   1.52
  3.   12
  4. 22
  5.   other
5. What is the type of this expression: 
"1" + 'a'
  1.   int
  2.   char
  3.   boolean
  4.   double
  5. other

The type is String so the answer is other.

6. What is the type of this expression: 
1 == 3
  1.   int
  2.   char
  3. boolean
  4.   double
  5.   other
7. What is the type of this expression: 
1 / 2
  1. int
  2.   char
  3.   boolean
  4.   double
  5.   other
8. What is the type of this expression: 
"abc".length()
  1. int
  2.   char
  3.   boolean
  4.   double
  5.   other
9. What is the type of this expression: 
"abc".length() == 3
  1.   int
  2.   char
  3. boolean
  4.   double
  5.   other
10. What is the type of this expression: 
"appearance".substring(2, 6)
  1.   int
  2.   char
  3.   boolean
  4.   double
  5. other

The type is String so the correct answer is other.

11. What is the type of this expression: 
"abc".toUpperCase()
  1.   int
  2.   char
  3.   boolean
  4.   double
  5. other

The type is String so the correct answer is other.

12. What is the output produced by the following three lines (when embedded in a complete program)? 
int a, b;
a = 3; b = 5;  
System.out.println(b * (a / b) + a % b);
  1.   1
  2.   2
  3. 3
  4.   6
  5.   other
13. What is the output produced by the following three lines (when embedded in a complete program)? 
int a, b;
a = 3; b = 5;  
System.out.println(b * a / b + a % b);
  1.   1
  2.   2
  3.   3
  4. 6
  5.   other
14. What is the output produced by the following code when embedded in a complete program? (Note that the program may or may not be indented correctly so think about it carefully.) 
int x = 3;
if (2 > x) 
  System.out.print("*"); 
else 
  System.out.print("*"); 
if (x < 2) 
  System.out.println("*"); 
System.out.print("*");
  1.   *
  2. **
  3.   ***
  4.   ****
  5.   other
15. What is the output produced by the following code when embedded in a complete program? (Note that the program may or may not be indented correctly so think about it carefully.) 
int x = 3;
if (x > 5) { 
  if (x < 10) 
    System.out.print("**"); } 
else 
  System.out.print("*"); 
  System.out.print("*");
  1.   *
  2. **
  3.   ***
  4.   ****
  5.   other
16. What is the output produced by the following code when embedded in a complete program? (Note that the program may or may not be indented correctly so think about it carefully.) 
int x = 3;
if (x <  5 || x > 10)  
  System.out.print("*"); 
if (x <  5 && x > 10) 
  System.out.print("*"); 
if (x < 10 && x >  5) 
  System.out.print("*"); 
if (x < 10 && x >  5) 
  System.out.print("*"); 
System.out.print("*");
  1.   *
  2. **
  3.   ***
  4.   ****
  5.   other
17. What is the output produced by the following code when embedded in a complete program? (Note that the program may or may not be indented correctly so think about it carefully.) 
int x = 3;
if (x <  5 || x > 10)  
  System.out.print("*"); 
else if (x <  5 && x > 10) 
  System.out.print("*"); 
else if (x < 10 && x >  5) 
  System.out.print("*"); 
else if (x < 10 && x >  5) 
  System.out.print("*"); 
else System.out.print("*");
  1. *
  2.   **
  3.   ***
  4.   ****
  5.   other
18. What is the output produced by the following code when embedded in a complete program? (Note that the program may or may not be indented correctly so think about it carefully.) 
if (2 <= 3 && 0 != 1) 
  System.out.print("*"); 
else 
  System.out.print("*"); 
System.out.print("*"); 
if (2 > 3 || 0 == 1) 
  System.out.print("*"); 
else 
  System.out.print("*"); 
System.out.print("*");
  1.   *
  2.   **
  3.   ***
  4. ****
  5.   other
19. What is the output produced by the following code when embedded in a complete program? 
boolean x = false; 
if (true) 
  System.out.print(10); 
else 
  System.out.print(1); 
x = x || !x; 
if (x) 
  System.out.print(0);   
else 
  System.out.print(00);
  1.   10
  2. 100
  3.   1000
  4.   10000
  5.   other
20. What is the output produced by the following code when embedded in a complete program? 
if (!false && false || true) {
  System.out.print(false); 
} else {
  System.out.print(true); 
}
  1.   true
  2. false
21. What is the output produced by the following code when embedded in a complete program? 
if (false && (!false || true)) {
  System.out.print(false); 
} else {
  System.out.print(true); 
}
  1. true
  2.   false
22. What is the output produced by the following code when embedded in a complete program? 
if (false && (false || !true)) {
  System.out.print(false); 
} else {
  System.out.print(true); 
}
  1. true
  2.   false
23. What is the output produced by the following code when embedded in a complete program? 
if (false && !(false || true)) {
  System.out.print(false); 
} else {
  System.out.print(true); 
}
  1. true
  2.   false
24. What is the output produced by the following code when embedded in a complete program? 
if (!false && (!false || !true)) {
  System.out.print(false); 
} else {
  System.out.print(true); 
}
  1.   true
  2. false
25. What is the output produced by the following code when embedded in a complete program? 
if (!false && !false || !true) {
  System.out.print(false); 
} else {
  System.out.print(true); 
}
  1.   true
  2. false
26. What is the output produced by the following code when embedded in a complete program? 
if (!(false && false || true)) {
  System.out.print(false); 
} else {
  System.out.print(true); 
}
  1. true
  2.   false
27. What is the output produced by the following code when embedded in a complete program? 
if (!true) {
  System.out.print(false); 
} else {
  System.out.print(true); 
}
  1. true
  2.   false
28. What is the output produced by the following code when embedded in a complete program? 
if (false) {
  System.out.print(false); 
} else {
  System.out.print(true); 
}
  1. true
  2.   false
29. What is the output produced by the following code when embedded in a complete program? 
if ((2 > 3) == false) {
  System.out.print(false); 
} else {
  System.out.print(true); 
}
  1.   true
  2. false
30. What is the output produced by the following code when embedded in a complete program? 
if (! (2 > 3)) {
  System.out.print(false); 
} else {
  System.out.print(true); 
}
  1.   true
  2. false
31. What is the output produced by the following code when embedded in a complete program? 
if (2 <= 3) {
  System.out.print(false); 
} else {
  System.out.print(true); 
}
  1.   true
  2. false
32. Are these two code fragments equivalent (do they always change x in the exact same way)?

Fragment 1 Fragment 2 
if (x == 8) 
  x = x + 3; 
else 
  x = 5;
 
if (x == 8)
  x = x + 3;
if (x != 8) 
  x = 5;

  1.   Yes.
  2. No.

They are almost equivalent. The only value of x for which they don't behave the same is 8 (eight).

For the following 5 (five) exercises consider the following method definitions: 

public static int f(int x) {
  return x + 1; 
}
public static int g(int x) { return x + 2; }
public static int h(int x) { return x - 2; }
public static int k(int x) { return x - 1; }
Here's how you find the answer to 33-37: 

frilled.cs.indiana.edu%cat One.java
class One {
    public static void main(String[] args) {
	
	System.out.println( g(2) ); 
	System.out.println( g(h(2)) ); 
	System.out.println( k(g(2) + h(2)) ); 
	System.out.println( f(0) + f(1) + f(2) ); 
	System.out.println( f(2) ); 
	
    }
    
    public static int f(int x) {
	return x + 1; 
    }
    public static int g(int x) { return x + 2; }
    public static int h(int x) { return x - 2; }
    public static int k(int x) { return x - 1; }
    
}
frilled.cs.indiana.edu%javac One.java
frilled.cs.indiana.edu%java One
4
2
3
6
3
frilled.cs.indiana.edu%
33. What does g(2) evaluate to?
  1.    0
  2.    1
  3.    2
  4.    3
  5. other

34. What does g(h(2)) evaluate to?
  1.    0
  2.    1
  3. 2
  4.    3
  5.   other
35. What does k(g(2) + h(2)) evaluate to?
  1.    0
  2.    1
  3.    2
  4. 3
  5.   other
36. What does f(0) + f(1) + f(2) evaluate to?
  1.    0
  2.    1
  3.    2
  4.    3
  5. other
37. What does f(2) evaluate to?
  1.    0
  2.    1
  3.    2
  4. 3
  5.   other
38. "true" is an example of what kind of constant?
  1.   int
  2.   char
  3.   boolean
  4. String
  5.   other
39. true is an example of what kind of constant?
  1.   int
  2.   char
  3. boolean
  4.   String
  5.   other
40. Assume that x is an integer variable. Simplify the following expression: 
!((x >= 4) && (x <= 4))
  1.   true
  2.   false
  3. x != 4
  4.   x == 4
  5.   other

Warning: Don't overlook the logical negation (bang!) at the front.

41. How many instance methods do you see defined below? 
class One {
  int balance; 
  int f() { return 1; } 
  static int g() { return 2; }
  One(int x) { this.balance = x; } 
  public static void main(String[] args) { }  
}
  1.    0
  2. 1
  3.    2
  4.    3
  5.   other
42. How many static methods do you see defined below? 
class One {
  int balance; 
  int f() { return 1; } 
  static int g() { return 2; }
  One(int x) { this.balance = x; } 
  public static void main(String[] args) { }  
}
  1.    0
  2.    1
  3. 2
  4.    3
  5.   other
43. How many instance variables do you see defined below? 
class One {
  int n; 
  int m; 
  int fun(int p) {
    int q = p + 1; 
    return q; 
  }
}
  1.    0
  2.    1
  3. 2
  4.    3
  5.   other
44. How many instance variables do you see defined below? 
class One {
  static int n;
  int m; 
  int fun(int p) {
    int q = p + 1; 
    return q; 
  }
}
  1.    0
  2. 1
  3.    2
  4.    3
  5.   other
45. How many instance variables do you see defined below? 
class One {
  static int n;
  int fun(int p) {
    int m; 
    int q = p + 1; 
    return q; 
  }
}
  1. 0
  2.    1
  3.    2
  4.    3
  5.   other
46. How many local variables do you see defined below? 
class One {
  static int n;
  int fun(int p) {
    int m; 
    int q = p + 1; 
    return q; 
  }
}
  1.    0
  2.    1
  3. 2
  4.    3
  5.   other
47. You compile and run this program. What is the output (or outcome)? 
class Wan {
    int value; 
    int addOne() { value += 1; return 0; } 
    void report() { System.out.println(value); } 
    public static void main(String[] args) {
      Wan a = new Wan(); 
      Wan b = new Wan(); 
      a.addOne(); 
      b.addOne(); 
      b.addOne(); 
      a.addOne(); 
      a.report(); 
    } 
}
  1.    0
  2.    1
  3. 2
  4.    3
  5.   other

The focus of this exercise and the next was the difference between static and non-static variables.

48. You compile and run this program. What is the output (or outcome)? 
class Wan {
    static int value; 
    int addOne() { value += 1; return 0; } 
    void report() { System.out.println(value); } 
    public static void main(String[] args) {
      Wan a = new Wan(); 
      Wan b = new Wan(); 
      a.addOne(); 
      b.addOne(); 
      b.addOne(); 
      a.addOne(); 
      a.report(); 
    } 
}
  1.    0
  2.    1
  3.    2
  4.    3
  5. other

This one prints a 4 (four) so the answer is other.

49. Which of the following expressions does NOT print a 4 (four)?
  1. System.out.println('P' - 'K');
  2. System.out.println(3 % 5 + 1);
  3. System.out.println("123".length() + 1);
  4. System.out.println((char)('3' + 1));
  5. System.out.println(16 / (1 + 1) / 2);
Note: There are no typos!
50. What's the output produced by the following lines (when embedded in a complete program)? 
String a = "blue"; 
String b = "berry"; 
System.out.println(
  "blueberry".substring(a.length(), b.length()));
  1. b
  2.   l
  3.   u
  4.   e
  5.   other
51. What gets printed when you compile and run the following program? 
public class A {
  public static void main(String[] args) {
    System.out.println(nuf(fun(3, 2), 1)); 
  } 
  public static int fun(int a, int b) {
    return a - b;
  } 
  public static int nuf(int b, int a) {
    return a - b; 
  }
}
  1. 0
  2.   1
  3.   2
  4.   3
  5.   other
There are no typos, so please don't rush!
52. What is the result of attempting to compile and run the following code? 
class Example {
  public static void main(String[] args) {
    Example e = new Example(); 
    System.out.println(e.fun(e.fun())); 
  } 
  int fun() { return 1; } 
  int fun(int n) { return 1 + n; } 
}
  1.   0
  2.   1
  3. 2
  4.   3
  5.   other
A201/A597/I210 Midterm Exam Wed Feb 13 2002 in RH100