- Consider the following code snippet:
Question: What operators does the code contain?arrayOfInts[j] > arrayOfInts[j+1]
Answer:[]
,>
,[]
,+
- Consider the following code snippet:
int i = 10; int n = i++%5;
- Question: What are the values of
i
andn
after the code is executed?
Answer:i
is 11, andn
is 0.
- Question: What are the final values of
i
andn
if instead of using the postfix increment operator (i++
), you use the prefix version (++i)
)?
Answer:i
is 11, andn
is 1.
- Question: To invert the value of a
boolean
, which operator would you use?
Answer: The logical complement operator "!".
- Question: Which operator is used to compare two values,
=
or==
?
Answer: The==
operator is used for comparison, and=
is used for assignment.
- Question: Explain the following code sample:
result = someCondition ? value1 : value2;
Answer: This code should be read as: "IfsomeCondition
istrue
, assign the value ofvalue1
toresult
. Otherwise, assign the value ofvalue2
toresult
."
- Change the following program to use compound assignments:
class ArithmeticDemo { public static void main (String[] args){ int result = 1 + 2; // result is now 3 System.out.println(result); result = result - 1; // result is now 2 System.out.println(result); result = result * 2; // result is now 4 System.out.println(result); result = result / 2; // result is now 2 System.out.println(result); result = result + 8; // result is now 10 result = result % 7; // result is now 3 System.out.println(result); } }Here is one solution:
class ArithmeticDemo { public static void main (String[] args){ int result = 3; System.out.println(result); result -= 1; // result is now 2 System.out.println(result); result *= 2; // result is now 4 System.out.println(result); result /= 2; // result is now 2 System.out.println(result); result += 8; // result is now 10 result %= 7; // result is now 3 System.out.println(result); } }- In the following program, explain why the value "6" is printed twice in a row:
The codeclass PrePostDemo { public static void main(String[] args){ int i = 3; i++; System.out.println(i); // "4" ++i; System.out.println(i); // "5" System.out.println(++i); // "6" System.out.println(i++); // "6" System.out.println(i); // "7" } }System.out.println(++i);
evaluates to 6, because the prefix version of++
evaluates to the incremented value. The next line,System.out.println(i++);
evaluates to the current value (6), then increments by one. So "7" doesn't get printed until the next line.