Solutions to Quiz #2

1.
Describe the effect of the following statement in Java,
where *number* is a variable of type *int*:

`number++;`

Answer:
When this statement is executed, the value that is stored in the variable
*number* is increased by 1. For exmple, if the value is 16 before the
statement is executed, then the value 17 will be stored in *number* after
the statment is executed.
(Note: This assumes that *number* has been declared to be of some numeric
type, such as *int* or *double*.)

2.
What is an *algorithm*?

Answer:
An algorithm is a **definite step-by-step procedure** for performing some
task, which is guaranteed to finish after a finte number of steps.

3. Show the exact output produced by the following code segment:

int n; n = 22; while (n > 0) { System.out.println( n % 2 ); n = n / 2; }

Answer: (The first time through the loop, the
value of n is 22, and n % 2 is 0, since 2 goes evenly into 22 with no
remainder. So the output from the first execution of the loop is a 0 on a line
by itself. The statement n = n / 2 sets n = 11,
and the loop is then repeated with this new value of n. Witn n = 11,
the value of n % 2 is 1, and the output is a 1 on a line by itself.
Overall, n takes on the values 22, 11, 5, 2, 1, and 0. When n becomes 0, the
loop ends. The outputs are 22 % 2, 11 % 2, 5 % 2, 2 % 2, and 1 % 2.
That is, the outputs are 0, 1, 1, 0, and 1. Note that the loop ends **before**
it has a chance to print 0 % 2.)

So, the exact ouput of the code segment is:

0 1 1 0 1

4.
Write an *if statement* to complete the
following program. If the user's input (*answer*) is 13, then the program
should output the message "Correct"; otherwise, the program should output
the message "Wrong".

public class Greet { public static void main(String[] args) { int answer; System.out.print("What is 5 + 8 ? "); answer = TextIO.getlnInt(); } }

Answer:

public class Greet { public static void main(String[] args) { int answer; System.out.print("What is 5 + 8 ? "); answer = TextIO.getlnInt();if ( answer == 13 ) { System.out.println("Correct"); } else { System.out.println("Wrong"); }} }