2004 Fall - CS 101: Test 3
Name ______________________________________UVA Email ID _________
Page 1 _______ / 10 1. (Bonus 2 points) What is your section? 101 Page 4 _______ / 17 101E Page 5 _______ / 25 Page 6 _______ / 20 Page 2 _______ / 10 Page 3 _______ / 18
Total _______ /100 2. (5 points) What is the output of the following code segment? int i = 0; while ( i > 0 ) { ++i; System.out.println("true"); }
3. (5 points) What is the output of the following code segment? for ( int i = 0; i < 2; ++i ) { for ( int j = 0; j < 2; ++j ) { break; } System.out.println ("outer"); } System.out.println ("finished");
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Fall 2004 - CS 101: Test 3
Name ______________________________________UVA Email ID _________
4. (5 points) What is the output of the following code segment? int counter1 = 0; int counter2 = 0; for ( int i = 0; i < 5; ++i ) { for ( int j = 0; j < 10; ++j ) { ++counter1; } ++counter2; } System.out.println ("counter1 = " + counter1); System.out.println ("counter2 = " + counter2);
5. (5 points) Write a code segment using a while loop that performs a comparable task as the following code segment. Assume Scanner variable stdin has already been defined. int sum = 0; for ( int i = 0; i < 10; ++i ) { int number = stdin.nextInt(); sum = sum + number; } System.out.println(sum);
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Fall 2004 - CS 101: Test 3
Name ______________________________________UVA Email ID _________
6. (5 points) What is the compiler error in the following code segment. int[] array = { 8, 7, 6, 5, 4, 3 }; int sum = 0; for ( int i = 0; i < array.length; ++i ) { sum = sum + array[i]; } if ( i == sum ) { System.out.println("Same"); } else { System.out.println("Different"); }
7. (5 points) Suppose class Widget has an int instance variable myData. Suppose that x and y are separately initialized Widget variables. Is it necessarily the case that x.myData must always equal y.myData? Why? (Use no more than TWENTY words to explain why).
8. (5 points) Suppose class Widget has a static int member variable theCount. Suppose that x and y are separately initialized Widget variables. Is it necessarily the case that x.theCount must always equal y.theCount? Why? (Use no more than TWENTY words to explain why).
9. (3 points) Draw a memory diagram for the following definition. int[] array;
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Fall 2004 - CS 101: Test 3
Name ______________________________________UVA Email ID _________
10. (3 points) Draw memory a diagram for the following definition. int[] array = new int[2];
11. (3 points) Draw a memory diagram for the following definition. int[] array = { 1, 2 };
12. (3 points) Draw a memory diagram for the following definition. String[] array = new String[2];
13. (3 points) Draw a memory diagram for the following definition. String[] array = { "A", "B" };
14. (5 points) Why do our examples in lecture define Scanner variable stdin in the following way Scanner stdin = new Scanner(System.in); rather than this way Scanner stdin = Scanner.create(System.in);
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Fall 2004 - CS 101: Test 3
Name ______________________________________UVA Email ID _________
For questions 1518 suppose class Coordinate has the following definition. public class Coordinate { int x; int y; public Coordinate(int a, int b) { this.x = a; this.y = b; } } 15. (5 points) Explain in TWENTY words or less why a Coordinate object has a toString() method.
16. (10 points) Define a public clone() member method with return type Object that returns a new Coordinate whose x and y values are the same as the x and y values of the this object.
17. (10 points) Define a boolean public method equals() that has a single Object parameter named v. The method should return false is v is not an instance of Coordinate. If v is a Coordinate then the method returns true if its x and y values match the x and y values of the this object; otherwise, the method returns false. Hint: if v is an instance of Coordinate then define a ...