Operators and Statements

Question 1

What would the operation 10/3 output?

Answer 1

3

Question 2

If two values have different data types and have an operator applied to them …

Answer 2

Java will automatically promote one of the values to the larger of the two data types

short a = 1;
int b = 1;
a+b will be an int

Question 3

If one of the values is integral and the other is floating point and they have an operator applied to them …

Answer 3

Java will automatically promote the integral value to the floating-point value’s data type

int a = 1;
double b = 1.0;
a+b will be a double

Question 4

When byte, short, and char are involved in a binary operation …

Answer 4

They are promoted to int before operation, even if neither operand is an int

short a = 10;
byte b = 5;
a/b will be an int

Question 5

What is the output?

int counter = 0;
System.out.println(counter); 
System.out.println(++counter);  
System.out.println(counter); 
System.out.println(counter--);  
System.out.println(counter);

Answer 5

0
1
1
1
0

Question 6

x & y

booleans

Answer 6

Result same as x && y

Question 7

x | y

booleans

Answer 7

Result same as x || y

Question 8

x ^ y

booleans

Answer 8

Exclusive or

Question 9

With x || y and x && y if x is true (for ||) or x is false (for && y) then …

Answer 9

y is not evaluated

Note: not the case for | and &

Question 10

Two references are equal if and only if ….

Answer 10

They point to the same object or both point to null

Question 11

What are the boolean values of 0 and 1?

Answer 11

Nothing! They mean nothing in the boolean world of Java!

Question 12

booleanExp ? exp1 : exp2

Answer 12

If booleanExp is true, then execute exp1, otherwise execute exp2

Question 13

switch statement syntax

Answer 13

switch (variableToTest) {
    case constantExp:
             //Code to run
             break;
    default:
             //Code to run

Question 14

What are the data types supported by switch statements?

Answer 14

1) byte and Byte
2) short and Short
3) char and Character
4) int and Integer
5) String
6) enum values

Question 15

What are the three types of values you can use for case values in a switch statement?

Answer 15

A literal, enum constant, or a final constant variable

Question 16

do-while statement syntax

Answer 16

do {
     //Code to be executed
} while (booleanExp);

Question 17

for-each loop syntax

Answer 17

for (datatype instance : collection) {
     // Code to be executed
}

Question 18

Statement Labels

Answer 18

You can add a label to a block statement to allow the application flow to jump to it or break from it.
Usually only used in loop structures, good for nested loops

MY_LABEL: for (int x : nums)

Question 19

How to break from a loop that is layers away

Answer 19

Add a label (MY_LABEL) to the loop, and code
break MY_LABEL;

Can do the same with continue