Variables

Question 1

An int always takes ___ bytes

Answer 1

4

Question 2

A fraction multiplied by an integer returns ____

Answer 2

zero

Question 3

To avoid truncation (operation using two integers)….

Answer 3

cast one of them to a double BEFORE the operation is applied (i.e. “a / (double) b” NOT “(double) (a/b)*. If at least one of the operands is a double, there is no need to cast the other one–it is promoted to a double automatically

Question 4

Simply saying (1/2) will return what?

Answer 4

0. This is because when one divides two integers, the resulting double is rounded DOWN to an integer

Question 5

== vs. .equals

Answer 5

== is true if and only if the two variables refer to exactly the same object (ADDRESSES). .equals compares the CONTENTS of the two objects (used for strings, primarily)

Question 6

De Morgan’s Laws

Answer 6

!(a && b) is the same as !a || !b

!(a || b ) is the same as !a && !b

Question 7

Short-circuit evaluation

Answer 7

If the value of the first operand is sufficient to determine the result, then the second operand is NOT evaluated. For example:
int x = 0, y = 3;
String op = “/”
if (op.equals(“/”) && (x!= 0) && (y/x > 2)
do stuff
else
do other stuff

This code WILL compile and execute without error because although y/x is undefined, we never get that far b/c the second operand fails