Operators in Java

Question 1

What is an expression built using?

Answer 1

Constants, variables, operators and method calls

Question 2

What are operators?

Answer 2

Symbols which are used in expressions to perform arithmetic or logical operations

Question 3

What is operand?

Answer 3

The variable or literal on which the operator is applied

Question 4

Name the three forms of operators

Answer 4

1. Unary
2. Binary
3. Ternary

Question 5

What is a unary operator?

Answer 5

An operator that has just one operand.

Question 6

Give examples of unary operators

Answer 6

+,-, ++, –, !

Question 7

What is a binary operator?

Answer 7

An operator that has two operands in known as binary operator

Question 8

Give examples of binary operators

Answer 8

+, %, >, &&, etc

Question 9

What is a ternary operator?

Answer 9

An operator that has three operands is known as a ternary operator

Question 10

Give example of a ternary operator

Answer 10

?:

Question 11

What are arithmetic operators?

Answer 11

+, -, *, /, %

Question 12

What is the result when two integers are divided?

Answer 12

The result of the division will also be an integer (the decimal part will be truncated

Question 13

What are the two forms of the plus and minus operators?

Answer 13

1. Unary form - adding/subtracting stuff

2. Preceding an operand

Question 14

Name the process of joining two strings together

Answer 14

Concatenation

Question 15

What are relational operators?

Answer 15

They determine the relationship between the two operands by comparing them

Question 16

What is the outcome of relational operators?

Answer 16

The outcome of these operations is a boolean value which is either true or false

Question 17

How many relational operators does Java provide?

Answer 17

6 types

Question 18

Name the six types of relational operators

Answer 18

1. Greater than (>)
2. Less than (=)
3. Less than or equal to (<=)
4. Not equal to (!=)

Question 19

What are logical operators?

Answer 19

They operate only on boolean operands and are used to construct simple decision making expressions

Question 20

Name some logical operators

Answer 20

1. Logical AND - &&
2. Logical OR - I I
3. Logical NOT - !

Question 21

What is the logical && operator?

Answer 21

It is a binary operator and is used to combine two conditions or expressions. The resultant value is a boolean value. The result is true if both values are two, and false if either is false

Question 22

What is the logical | | operator?

Answer 22

It is a binary operator and is used to combine two conditions or expressions. The resultant value is also a boolean value. The result is true if both or either is true, false if both are wrong

Question 23

What is the logical NOT operator?

Answer 23

It is a unary operator and is written before a single operand. It negates the result of the expression following it

Question 24

What are assignment operators?

Answer 24

It is used to assign the value of an expression to a variable

Question 25

What type of operator is the assignment operator?

Answer 25

Binary operator

Question 26

Give the difference between = and ==

Answer 26

= is an assignment operator, whereas == is a comparison operator

Question 27

What are shorthand assignment operators?

Answer 27

Several variations of the assignment operator that are offered in Java

Question 28

Give two advantages of using shorthand operators

Answer 28

1. They save a little bit of typing time
2. The use of shorthand operators result in an efficient code as they are implemented most efficiently by Java run-time environment as compared to their long forms

Question 29

State the main shorthand operators

Answer 29

1. +=
2. -=
3. *=
4. /=
5. %=

Question 30

What are increment and decrement operators?

Answer 30

The operators ++ and –are increment and decrement operators, respectively

Question 31

What type of operators are increment and decrement operators?

Answer 31

Unary

Question 32

What is the rule in postfix increment?

Answer 32

First use, then increment

Question 33

Explain the process of postfix increment

Answer 33

1. Initially, the value of a variable y is 10, and the value of z us not defined
2. You first use y, which is 10, hence z is assigned to the value 15
3. You increment the value of y by 1. Thus, the final value of y = 16

Question 34

What is the rule in the Prefix increment?

Answer 34

First increment, then use

Question 35

What is the conditional operator?

Answer 35

It is also called a ternary operator because it has three operands

Question 36

What is the syntax of a conditional operator?

Answer 36

boolean-expression ? expression 1 : expression 2

Question 37

What is precedence of operators?

Answer 37

Each operator has a precedence associated with it. Precedence is the priority of an operator according to which it is evaluated. This precedence is used to determine the order of evaluation of an expression involving more than one operator.

Question 38

What is associativity?

Answer 38

If two operators have the same precedence, then they are either evaluated from “Left to Right” or from “Right to Left”. This is termed as associativity, which tells the direction of execution of operators

Question 39

Name the two steps involved in creating the object of the class datatype

Answer 39

1. Declaring a variable of the class type

2. Allocating memory for the object where the details of the object can be stored

Question 40

What is the new operator used for?

Answer 40

To allocate memory for the object

Question 41

Give the syntax for creating an object of a class

Answer 41

Classname objectname = new Classname();

Question 42

What does it mean when a class is being instantiated?

Answer 42

An instance of the class is being created

Question 43

What is the purpose of the dot operator?

Answer 43

Once the objects have been declared and the memory has been allocated, member variables and member methods can be accessed using the dot operator

Question 44

Give the syntax of the dot operator

Answer 44

Objname.memberVariable;

Objname.memberMethod();

Question 45

What do you use to determine the order of evaluation of the operators when several operators appear in an expression?

Answer 45

Precedence and associativity

Question 46

What does an arithmetic expressoin represent?

Answer 46

A numeric value

Question 47

When does a type conversion take place?

Answer 47

When an arithmetic expression consists of constants and variables of different data types (mixed expression)

Question 48

What is type conversion?

Answer 48

It is a process that converts a value of one data type to another data type

Question 49

What are implicit type conversions?

Answer 49

The type conversions which are automatically performed by the Java compiler

Question 50

Give other names for implicit type conversions

Answer 50

Automatic type conversion, type promotion, widening conversion or coercion

Question 51

What are explicit type conversions?

Answer 51

In a case where a data type smaller than another has to hold a value of the bigger data type, a programmer has to force the conversion

Question 52

What needs to be done to create a conversion between two incompatible types?

Answer 52

A cast must be used, which is simply an explicit type conversion

Question 53

What is the drawback of using a cast?

Answer 53

It can lead to loss of precision. For example, when a double value is assigned to an int type, the fractional component is lost