CSCI A201/A597

Final Exam

Answers

The price of some item is stored in a double variable named cost. The sales tax on this item is 5 percent. Which of the following statements will increase the value in cost by the sales tax?

1. cost * .05;
2. cost + cost * .05;
3. cost = cost * .05;
4. cost = cost + cost * .05;
5. cost = Integer.parseInt(cost * .05);

System.out.println(2 - 4 / 3); 

1. an error message
2. 1
3. 0.7
4. 1.3
5. 0.66

1. "age = + 20"
2. "age=20"
3. "age = 20"
4. 20
5. this expression contains a syntax error

The user runs a program containing the following fragment and then types 29 at the prompt.

int w;
ConsoleReader c = new ConsoleReader(System.in);
System.out.print("Enter w: "); 
w = c.readInt();
int a, b;
a = w / 16;
b = w % 16;
System.out.println(a + b);

1. 113
2. 14
3. "1 13"
4. "13 1"
5. an error message

int x, y;
x = 5;
y = 3;
x = x + 1;
y = x;
x = x - 1;
System.out.println("x = " + x + ", y = " + y);

1. x = 3, y = 5
2. x = 3, y = 3
3. x = 4, y = 4
4. x = 3, y = 4
5. none of the above

String quote = "There's a tomato in every automaton!";

1. "utomat"
2. "utomato"
3. "tomato"
4. "tomaton"
5. none of the above

The user runs a program containing the following fragment and then types Alice at the prompt.

ConsoleReader c = new ConsoleReader(System.in);
String name;
System.out.print("Enter your name: "); 
name = c.readLine();
name = name.toUpperCase();
System.out.println("Hello " + name + "!");

1. Hello Alice!
2. Hello ALICE!
3. HELLO Alice!
4. HELLO ALICE!
5. none of the above

String vehicle = "snowmobile";

1. vehicle
2. "vehicle"
3. vehicle.substring(0, 5)
4. vehicle.length()
5. vehicle + vehicle.length()

At a certain university, if a student drops a class on or before September 20 (that is, 9/20), then no record of the course appears on the student's transcript. A grade of W appears if the withdrawal takes place on or before October 15 (that is, 10/15), and a grade of F or I is recorded otherwise. Assume that the month and the day that a student withdraws are stored in two separate int variables called month and day. Select the condition that should be inserted into the following if statement

if ( /* What goes here? */ )
   System.out.println("Assign a grade of W."); 

1. (month == 9 || month == 10) && (15 < day && day <= 20)
2. (month >= 9) && (day > 20 || day <= 15)
3. (month == 9 && day > 20) || (month == 10 && day <= 15)
4. (month == 9 && day > 20) && (month == 10 && day <= 15)
5. (month >= 9 && month <= 10) && (day <= 15 || day > 20)

Which of the following expressions is NOT logically equivalent to (x <= y)?

1. (y >= x)
2. (x < y) && (x == y)
3. (x == y) || (x < y)
4. (x - y) <= 0
5. (x <= y) && (x == x)

   ---

   Question # : 11. Consider the following code fragment:

   int t = 5;
   if (t >= 5)
      System.out.print("Wicked ");
   else if (t >= 3)
      System.out.print("Witch ");
   if (t <= 7)
      System.out.print("of the West");
   

   What gets printed when you run it?
   1. Wicked
   2. Wicked Witch
   3. Wicked of the West
   4. Witch of the Wicked West
   5. Witch

   ---

   Question # : 12. Are these two code fragments equivalent?

   z = z + 1; if (x <= y) z = z + 1;

   if (x > y) z = z + 1; else if (x <= y) z = z + 2;

   1. yes
   2. no

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   Question # : 13. What does the following program fragment print? Read carefully.

   String s = "dogfood", t = "dogfood";
   if (!s.equals(t))
      System.out.print("You could've fooled me! ");
   else
      System.out.print("Figures. ");
      System.out.print("I'm outta here!");
   

   1. You could've fooled me! Figures.
   2. Figures. I'm outta here!
   3. You could've fooled me!
   4. I'm outta here!
   5. You could've fooled me! I'm outta here!

   ---

   Question # : 14. Assume that x is an integer variable. Simplify the following boolean expression:

   (x > 3) || (x < 5)

   1. x == 4
   2. true
   3. x > 3
   4. x < 5
   5. none of the above

   ---

   Question # : 15. Assume that x and y are integer variables. Consider the following nested if statement.

   if (x > 3) 
   {
      if (x <= 5)
         y = 1;
      else if (x != 6)
              y = 2;
           else
              y = 3;
   } else
      y = 4;

   If y has the value 2 after executing the above program fragment, then what do you know about x?
   1. (x == 4) || (x == 6)
   2. x >= 7
   3. (x != 6) && (x < 5)
   4. (x <= 3)
   5. none of the above

   ---

   Question # : 16. Assume that x is an integer variable. Simplify the following boolean expression:

   (x > 3) && (x < 5)

   1. x == 4
   2. true
   3. x > 3
   4. x < 5
   5. none of the above

   ---

   Question # : 17. Assume that x is an integer variable. Simplify the following boolean expression.

   !(((x > 0) || (x == 0)) && (x < 10))

   Warning: Don't overlook the logical negation (bang!) at the front.
   1. (x < 0) || (x >= 10)
   2. (x < 0) && (x >= 10)
   3. x >= 10
   4. (x != 0) || (x >= 10)
   5. none of the above

   ---

   Question # : 18. Given the following declaration:

   String word = "drow";

   What does word.charAt(3) evaluate to?
   1. "r"
   2. 'o'
   3. 'r'
   4. "o"
   5. none of the above

   ---

   Question # : 19. Which of the following expressions does not evaluate to 5?
   1. '5' - '0'
   2. (4 * 5 + 3) / 4
   3. ("01" + "0" + "12").length()
   4. 8 - 1 - 2
   5. '5'

   ---

   Question # : 20. Consider the following class definition. How many instance members does it define for objects of class One?

   class One {
     public static void main(String[] args) {
       int a = 0, b = 1;
       System.out.println(" a + b = " + (a + b));
     }
   }

   1. One cannot create objects of this class, because there is no constructor defined.
   2. No instance members, the objects will be empty.
   3. One instance member.
   4. Two variables and a method.

   ---

   Question # : 21. Is this an example of an infinite loop?

   int x = 10;
   while (x == 0) {
     x = x + 1;
     System.out.println(x);
     x = x % x;
   } 

   Don't rush, think carefully.
   1. Yes
   2. No

      ---

      Question # : 22. Is this an example of an infinite loop?

      int x = 10;
      do { 
        x = x + 1;
        System.out.println(x);
        x = x % x;
      } while (x == 0); 

      Don't rush, think carefully.
      1. Yes
      2. No

      ---

      Question # : 23. What is wrong with this class definition?

      class Avg {
        public static void main(String[] args) {
          double a = 1;
          double b = a + 1;
          double c = b + 1;
          System.out.println(findAvg(a, b, c));
        }
        double findAvg(double a, double b, double c) {
          return (a + b + c) / 3.0;
        }
      }

      How can you fix it so that it works when you invoke main()?

      1. turn findavg into a public method
      2. turn findavg into a static method
      3. turn findavg into a void method
      4. none of the above

      ---

      Question # : 24. Consider the following code:

      class One {
        static int var1 = 1;
        static int var2;
        public static void main(String[] args) {
          int var3 = var1 + var2;
          System.out.println(var1 + var2 + var3);
        }
      }

      What is the result of trying to compile and run it?
      1. 0
      2. 1
      3. The code does not compile because var3 is not initialized correctly.
      4. The code does not compile because var2 is not initialized at all.
      5. none of the above

      ---

      Question # : 25.

      Can you initialize an array of three boolean values to all true the way presented below?

      boolean[] b;
      b = { true, true, true };

      1. Yes.
      2. No.

      ---

      Question # : 26. By default integer values are of type int, and floating point values are of type double. However, you can force an integer value to be a long by placing an L after it. You can also force a floating-point value to be a float by placing an F after it.

      Knowing this, consider the following program:

      class Example {
        public static void main(String[] args) {
          Example e = new Example();
          e.test(5);
        }
        int test(int i) {
          System.out.println("long");
          return 1;
        }
        void test(long i) {
          System.out.println("int");
        }
      }

      What is the result of attempting to compile and run it?
      1. The program does not compile because the compiler cannot distinguish between the two test() methods provided.
      2. The program compiles and runs and "long" appears in the standard output.
      3. The program compiles and runs and "int" appears in the standard output.
      4. The program compiles and runs and "long" appears in the standard output followed by a 1.

      ---

      Question # : 27. Which of these defines a valid main() method (that will run when you invoke java on the class that contains the method, from the command line)?
      1. public static void main(String args) { }
      2. public static void main(String[]) { }
      3. public static void main(string[] args) { }
      4. public static void main(args) { }
      5. none of the above

      ---

      Question # : 28. How can you access the word "jini" from the following command-line invocation:

      java java jini java jini java

      1. args[1]
      2. args[2]
      3. args[3]
      4. args[4]
      5. args[5]
      Please mark just one answer on the answer sheet.

      ---

      Question # : 29. What will appear in the standard output when you run the Tester class below?

      class Tester {
      
        int var;
      
        Tester (double var) { this.var = (int)var;            }
        Tester (int var)    { this("hello");                  }
        Tester (String s)   { this(); System.out.println(s);  }
        Tester ()           { System.out.println("good-bye"); }
      
        public static void main(String[] args) {
          Tester t = new Tester(Math.sqrt(2));
        }
      
      }

      1. nothing at all
      2. hello
      3. 1.4142135623730951
      4. hello followed by good-bye
      5. good-bye followed by hello

      ---

      Question # : 30. What is printed by the following program?

      public class A {
        public static void main(String[] args) {
          int x = 1;
          System.out.print(fun(x) + " "); 
          System.out.print(x + " "); 
        } 
        public static int fun(int x) {
          x = x - 1; 
          return x; 
        } 
      }

      1. 1 0
      2. 1 1
      3. 0 1
      4. 0 0
      5. none of the above

      ---

      Question # : 31. What is printed by the following program?

      public class A {
        public static void main(String[] args) {
          int[] x = {1, 2, 3, 4, 5};
          System.out.print(fun(x) + " "); 
          System.out.print(x[2] + " "); 
        } 
        public static int fun(int[] x) {
          x[2] = x[2] - 1; 
          return x[2]; 
        } 
      }

      1. 3 3
      2. 3 2
      3. 2 3
      4. 2 2
      5. none of the above

      ---

      Question # : 32. Assume that x is an integer variable that appears in the following boolean expression:

      (x >= 14) && (x <= 12)

      Which of the following is a simplification of the expression?
      1. x == 13
      2. (x < 14) || (x > 12)
      3. true
      4. false
      5. none of the above

      ---

      Question # : 33. Assume that x is an integer variable that appears in the following expression:

      (x >= 12) || (x <= 14)

      Which of the following is a simplification of the expression?
      1. x != 13
      2. (x < 14) && (x > 12)
      3. true
      4. false
      5. none of the above

      ---

      Question # : 34. What is printed by the following program?

      public class A {
        public static void main(String[] args) {
          System.out.print(fun(5) + " "); 
        } 
        public static int fun(int x) {
          System.out.print(x + " "); 
          return x + 1;
        } 
      }

      1. 5
      2. 6
      3. 5 5
      4. 5 6
      5. none of the above

      ---

      Question # : 35. What is printed by the following program fragment?

      int x = 1, y = 1;
      y += x; 
      x += y;
      System.out.println(x + " " + y);

      1. 1 2
      2. 2 1
      3. 2 3
      4. 3 2
      5. none of the above

      ---

      Question # : 36. Given the following definition

      public static String mix(String s, String t) {
        String ans = ""; 
        int slen = s.length(), tlen = t.length(); 
        for (int i = 0; i < slen && i < tlen; i++) {
          ans = ans + t.charAt(i) + s.charAt(i);
        } 
        return ans; 
      }

      what does

      mix ("123", "45678")

      evaluate to?
      1. 12345678
      2. 142536
      3. 415263
      4. 123456
      5. none of the above

      ---

      Question # : 37. What is printed by the following program:

      public class A {
        public static void main(String[] args) {
          int yo = 12; 
          System.out.println(yo(yo)); 
        }
        public static boolean yo (int yo) {
          if (yo == 12)
            return true;
          return false;  
        } 
      }

      1. true
      2. false
      3. this code will not compile
      4. this code compiles but produces a run-time error
      5. none of the above

      ---

      Question # : 38. What is printed by the following program:

      public class A {
        public static void main(String[] args) {
          System.out.println(fun(1, fun(fun(2, fun(3, 4)), 5))); 
        } 
        public static int fun(int a, int b) {
          return a + b;
        } 
      } 

      1. 5
      2. 12
      3. 15
      4. 17
      5. 25

      ---

      Question # : 39. Is this an infinite loop?

      for (int i = 0; i < 10; i--) 
        System.out.println(i);

      1. yes
      2. no

      ---

      Question # : 40. Is this an infinite loop?

      for (int i = 1; i != 10; i = i + 3) 
        System.out.println(i);
      

      1. yes
      2. no

      ---

      Question # : 41. Given the following declaration, what does a[a[a[a[0]]]] evaluate to?

      int[] a = {1, 2, 3, 4, 5}; 

      1. 1
      2. 2
      3. 3
      4. 4
      5. 5

      ---

      Question # : 42. Given the following declaration, what does a[1 + a[1 + a[0]]] evaluate to?

      int[] a = {1, 2, 3, 4, 5}; 

      1. 1
      2. 2
      3. 3
      4. 4
      5. 5

      ---

      Question # : 43. Assume the following two arrays:

      String[] name = {"One", "Two", "Three", "Four", "Five"};
      boolean[] mark = {false, true, true, false, true}; 

      And a method fun with the following definition:

      public static String fun(String[] a, boolean[] b) {
        for (int i = 0; i < b.length; i++) {
          if (b[i]) {
            return a[i]; 
          }
        }
        return "One"; 
      }

      What does fun(name, mark) evaluate to?
      1. One
      2. Two
      3. Three
      4. Four
      5. none of the above

      ---

      Question # : 44. Now assume that the arrays are like this:

      String[] name = {"One", "Two", "Three", "Four", "Five"};
      boolean[] mark = {false, false, false, false, false}; 

      and the method still has the same definition:

      public static String fun(String[] a, boolean[] b) {
        for (int i = 0; i < b.length; i++) {
          if (b[i]) {
            return a[i]; 
          }
        }
        return "One"; 
      }

      What does fun(name, mark) evaluate to?
      1. One
      2. Two
      3. Three
      4. Four
      5. none of the above

      ---

      Question # :45. Exactly how many question marks will appear on the screen when the following program fragment is executed?

      for (int x = 0; x < 3; x++) {
        for (int y = -3; y < 0; y++) {
          System.out.print("?"); 
        } 
      } 

      1. 4
      2. 6
      3. 9
      4. 16
      5. none of the above

      ---

      Question # : 46. What does the following program fragment print?

      int[] a = new int[5]; 
      a[0] = 10;
      for (int i = 1; i < a.length; i++) 
        a[i] = a[i-1]-1;
      int value = a[0];
      for (int i = 0; i < a.length; i++) 
        if (value > a[i]) 
          value = a[i]; 
      System.out.println(value); 
      

      1. 3
      2. 0
      3. 4
      4. 1
      5. none of the above

      ---

      Question # : 47. What does the following program print?

      int[][] a = { {1, 2, 3, 4}, 
                    {2, 3, 4, 1},
                    {3, 4, 1, 2}, 
                    {4, 1, 2, 3}};     
      int sum = 0; 
      for (int i = 0; i < a.length; i++) {
        for (int j = 0; j < a[i].length; j++) {
          if (a[i][j] % 2 == 0) 
            sum = sum + a[i][j]; 
        } 
      }
      System.out.println(sum); 
      

      1. 6
      2. 12
      3. 20
      4. 24
      5. none of the above

      ---

      Question # : 48. What does the following program print?

      int[][] a = { {1, 2, 3, 4}, 
                    {2, 3, 4},
                    {3, 4}, 
                    {4}};     
      int sum = 0; 
      for (int i = 0; i < a.length; i++) {
        for (int j = 0; j < a[i].length; j++) {
          if (a[i][j] % 2 == 0) 
            sum = sum + a[i][j]; 
        } 
      }
      System.out.println(sum); 
      

      1. 6
      2. 12
      3. 20
      4. 24
      5. none of the above

      ---

      Question # : 49. What does the following program print?

      int[][] a = { {1, 2, 3, 4}, 
                    {2, 3, 4},
                    {3, 4}, 
                    {4}};     
      int sum = 0; 
      for (int i = 0; i < a.length; i++) {
        for (int j = 0; j < a[i].length; j++) {
          if (a[i][j] % 2 == 0) 
            sum = sum + 1; 
        } 
      }
      System.out.println(sum); 
      

      1. 6
      2. 12
      3. 20
      4. 24
      5. none of the above

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   August 11, 2000 in Lindley Hall 102 SWAIN EAST 140 (1:30pm-2:30pm)