Loops and Files Exam Questions Chapter.4

Starting Out with Java: From Control Structures through Objects 7e (Gaddis)

Chapter 4 Loops and Files

TRUE/FALSE

1. When the break statement is encountered in a loop, all the statements in the body of the loop that appear after it are ignored, and the loop prepares for the next iteration.

2. When the continue statement is encountered in a loop, all the statements in the body of the loop that appear after it are ignored, and the loop prepares for the next iteration.

3. A file must always be opened before using it and closed when the program is finished using it.

4. In a for loop, the control variable is always incremented.

5. The do-while loop must be terminated with a semicolon.

6. The do-while loop is ideal in situations where you always want the loop to iterate at least once.

7. When you pass the name of a file to the PrintWriter constructor and the file already exists, it will be erased and a new empty file with the same name will be created.

8. When you open a file with the PrintWriter class, the class can potentially throw an IOException.

9. The while loop is always the best choice in situations where the exact number of iterations is known.

10. Java provides a set of simple unary operators designed just for incrementing and decrementing variables.

11. The while loop has two important parts: (1) a boolean expression that is tested for a true or false value, and (2) a statement or block of statements that is repeated as long as the expression is true.

12. In a for loop, the control variable cannot be initialized to a constant value and tested against a constant value.

MULTIPLE CHOICE

1. A loop that repeats a specific number of times is known as a(n) __________ loop.

2. A __________ loop will always be executed at least once.

3. A __________ is a value that signals when the end of a list of values has been reached.

4. Before entering a loop to compute a running total, the program should first

5. An item that separates other items is known as a

6. A loop that executes as long as a particular condition exists is called a(n) __________ loop.

7. A(n) __________ is a special value that cannot be mistaken as a member of a list of data items and signals that there are no more data items to be processed.

8. The variable used to keep a running total in a loop is called a(n) __________.

9. In all but very rare cases, loops must contain, within themselves

10. The __________ loop is ideal in situations where the exact number of iterations is known.

11. The __________ loop is ideal in situations where you always want the loop to iterate at least once.

12. If a loop does not contain, within itself, a valid way to terminate, it is called a(n) __________ loop

13. Assume that inputFile references a Scanner object that was used to open a file. Which of the following while loops is the correct way to read data from the file until the end of the file is reached?

14. When working with the PrintWriter class, which of the following import statements should you have near the top of your program?

15. Assuming that inputFile references a Scanner object that was used to open a file, which of the following statements will read an int from the file?

16. Which of the following statements opens a file named MyFile.txt and allows you to read data from it?

17. Which of the following statements opens a file named MyFile.txt and allows you to append data to its existing contents?

18. Given the following statement, which statement will write the string "Calvin" to the file DiskFile.txt?

PrintWriter diskOut = new PrintWriter("DiskFile.txt");

19. Which of the following is the method you can use to determine whether a file exists?

20. What will be the value of x after the following code is executed?

int x = 10;

while (x < 100)

{

x += 100;

}

21. What will be the values of x and y as a result of the following code?

int x = 25, y = 8;

x += y++;

22. How many times will the following do-while loop be executed?

int x = 11;

do

{

x += 20;

} while (x > 100);

23. What will be the value of x after the following statements are executed?

int x = 10;

for (int y = 5; y < 20; y +=5)

x += y;

24. How many times will the following do-while loop be executed?

int x = 11;

do

{

x += 20;

} while (x <= 100);

25. How many times will the following for loop be executed?

for (int count = 10; count <= 21; count++)

System.out.println("Java is great!");

26. What will be the value of x after the following code is executed?

int x, y = 15;

x = y--;

27. What will be the value of x after the following code is executed?

int x, y = 4, z = 6;

x = (y++) * (++z);

28. What will be printed after the following code is executed?

for (int number = 5; number <= 15; number +=3)

System.out.print(number + ", ");

29. What will be the values of x aand y after the following code is executed?

int x = 12, y = 5;

x += y--;

30. What will be the values of x and y after the following code is executed?

int x, y = 15, z = 3;

x = (y--) / (++z);

31. What will be the value of x after the following code is executed?

int x = 10, y = 20;

while (y < 100)

{

x += y;

y += 20;

}

32. What will be the value of x after the following code is executed?

int x = 10, y = 20;

while (y < 100)

{

x += y;

}

33. Which is a control structure that causes a statement or group of statements to repeat?

34. Each repetition of a loop is known as a(n) __________.

35. Which of the following are pre-test loops?

36. The variable that controls the number of times a loop iterates is known as a(n) __________.

37. The __________ loop allows the user to decide on the number of iterations.

38. In the following code, what values could be read into number to terminate the while loop?

Scanner keyboard = new Scanner(System.in);

System.out.print("Enter a number: ");

int number = keyboard.nextInt();

while (number < 100 && number > 500)

{

System.out.print("Enter another number: ");

number = keyboard.nextInt();

}

39. In the following code, what values could be read into number to terminate the while loop?

Scanner keyboard = new Scanner(System.in);

System.out.print("Enter a number: ");

int number = keyboard.nextInt();

while (number < 100 || number > 500)

{

System.out.print("Enter another number: ");

number = keyboard.nextInt();

}

40. Which of the following expressions will generate a random number in the range of 1 through 10?

41. Which of the following statements will create an object from the Random class?

42. A random number, created as an object of the Random class, is always a(n) __________.

MULTIPLE RESPONSE

1. Select all that apply. Which of the following steps is normally performed by a for loop?

2. Select all that apply. Which method of the Random class will return a random number within the range of 0.0 and 1.0?