Exam #1

Question 1

What is the difference between the following two:
(double) 5 / 2
(double) (5 / 2)

Answer 1

Only the first one will result in a double.

Question 2

What is the difference between the following two:
(double) 3.5
Math.round(3.5)

Answer 2

The first one will just drop the decimal.
The second one will actually round upwards.

Question 3

How would I read this?
false && true || false

Answer 3

&& has higher priority than ||.
False

Question 4

How would I read this?
true || false

Answer 4

true

Question 5

How would I read this?
false && false

Answer 5

false

Question 6

What is De Morgan’s laws?

Answer 6

!(A && B) ≡ (!A) || (!B)
!(A || B) ≡ (!A) && (!B)

Question 7

What is the fourth letter?
She ate that.

Answer 7

a space

Question 8

What is a compiler?

Answer 8

Translates an entire code into binary in many steps

Question 9

What is an interpreter?

Answer 9

Translates code one step or line at a time.

Question 10

What type of language is Java?

Answer 10

A hybrid language (compiles and then interprets)

Question 11

What is the variable?
What is the literal?
What is the declaration statement?
What is the assignment statement?
int a;
a = 17;

Answer 11

a
17
int = a;
a = 17;

Question 12

What must variables start with?

Answer 12

letter
$
underscore

Question 13

Compile Time error vs. Runtime Error

Answer 13

• Will not compile correctly
• Something wrong in syntax
  vs.
• Your code will not end
• Something is wrong while running it

Question 14

Primitive vs Reference type

Answer 14

Primitive stores the actual value for a variable
Reference refers to the address of a primitive

Question 15

What is the difference?
5 / 0
5.0 / 0

Answer 15

Error
Infinity

Question 16

When does a number truncate?

Answer 16

When a double –> int it loses its decimal places

Question 17

What is concatenation?

Answer 17

Adding Strings together

Question 18

Can int be converted to double?
Can double be converted to int?

Answer 18

Yes
No

Question 19

How do you convert a double to int?

Answer 19

(int) double
(int) 5.6 –> 5

Question 20

How do you do an enhanced for loop?

Answer 20

// Random Array here

for (class name : array name) {
function that affects each object
}