## Assignment Operator Java Definition

## Java - Basic Operators

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Java provides a rich set of operators to manipulate variables. We can divide all the Java operators into the following groups −

- Arithmetic Operators
- Relational Operators
- Bitwise Operators
- Logical Operators
- Assignment Operators
- Misc Operators

## The Arithmetic Operators

Arithmetic operators are used in mathematical expressions in the same way that they are used in algebra. The following table lists the arithmetic operators −

Assume integer variable A holds 10 and variable B holds 20, then −

Show Examples

Operator | Description | Example |
---|---|---|

+ (Addition) | Adds values on either side of the operator. | A + B will give 30 |

- (Subtraction) | Subtracts right-hand operand from left-hand operand. | A - B will give -10 |

* (Multiplication) | Multiplies values on either side of the operator. | A * B will give 200 |

/ (Division) | Divides left-hand operand by right-hand operand. | B / A will give 2 |

% (Modulus) | Divides left-hand operand by right-hand operand and returns remainder. | B % A will give 0 |

++ (Increment) | Increases the value of operand by 1. | B++ gives 21 |

-- (Decrement) | Decreases the value of operand by 1. | B-- gives 19 |

## The Relational Operators

There are following relational operators supported by Java language.

Assume variable A holds 10 and variable B holds 20, then −

Show Examples

Operator | Description | Example |
---|---|---|

== (equal to) | Checks if the values of two operands are equal or not, if yes then condition becomes true. | (A == B) is not true. |

!= (not equal to) | Checks if the values of two operands are equal or not, if values are not equal then condition becomes true. | (A != B) is true. |

> (greater than) | Checks if the value of left operand is greater than the value of right operand, if yes then condition becomes true. | (A > B) is not true. |

< (less than) | Checks if the value of left operand is less than the value of right operand, if yes then condition becomes true. | (A < B) is true. |

>= (greater than or equal to) | Checks if the value of left operand is greater than or equal to the value of right operand, if yes then condition becomes true. | (A >= B) is not true. |

<= (less than or equal to) | Checks if the value of left operand is less than or equal to the value of right operand, if yes then condition becomes true. | (A <= B) is true. |

## The Bitwise Operators

Java defines several bitwise operators, which can be applied to the integer types, long, int, short, char, and byte.

Bitwise operator works on bits and performs bit-by-bit operation. Assume if a = 60 and b = 13; now in binary format they will be as follows −

a = 0011 1100

b = 0000 1101

-----------------

a&b = 0000 1100

a|b = 0011 1101

a^b = 0011 0001

~a = 1100 0011

The following table lists the bitwise operators −

Assume integer variable A holds 60 and variable B holds 13 then −

Show Examples

Operator | Description | Example |
---|---|---|

& (bitwise and) | Binary AND Operator copies a bit to the result if it exists in both operands. | (A & B) will give 12 which is 0000 1100 |

| (bitwise or) | Binary OR Operator copies a bit if it exists in either operand. | (A | B) will give 61 which is 0011 1101 |

^ (bitwise XOR) | Binary XOR Operator copies the bit if it is set in one operand but not both. | (A ^ B) will give 49 which is 0011 0001 |

~ (bitwise compliment) | Binary Ones Complement Operator is unary and has the effect of 'flipping' bits. | (~A ) will give -61 which is 1100 0011 in 2's complement form due to a signed binary number. |

<< (left shift) | Binary Left Shift Operator. The left operands value is moved left by the number of bits specified by the right operand. | A << 2 will give 240 which is 1111 0000 |

>> (right shift) | Binary Right Shift Operator. The left operands value is moved right by the number of bits specified by the right operand. | A >> 2 will give 15 which is 1111 |

>>> (zero fill right shift) | Shift right zero fill operator. The left operands value is moved right by the number of bits specified by the right operand and shifted values are filled up with zeros. | A >>>2 will give 15 which is 0000 1111 |

## The Logical Operators

The following table lists the logical operators −

Assume Boolean variables A holds true and variable B holds false, then −

Show Examples

Operator | Description | Example |
---|---|---|

&& (logical and) | Called Logical AND operator. If both the operands are non-zero, then the condition becomes true. | (A && B) is false |

|| (logical or) | Called Logical OR Operator. If any of the two operands are non-zero, then the condition becomes true. | (A || B) is true |

! (logical not) | Called Logical NOT Operator. Use to reverses the logical state of its operand. If a condition is true then Logical NOT operator will make false. | !(A && B) is true |

## The Assignment Operators

Following are the assignment operators supported by Java language −

Show Examples

Operator | Description | Example |
---|---|---|

= | Simple assignment operator. Assigns values from right side operands to left side operand. | C = A + B will assign value of A + B into C |

+= | Add AND assignment operator. It adds right operand to the left operand and assign the result to left operand. | C += A is equivalent to C = C + A |

-= | Subtract AND assignment operator. It subtracts right operand from the left operand and assign the result to left operand. | C -= A is equivalent to C = C – A |

*= | Multiply AND assignment operator. It multiplies right operand with the left operand and assign the result to left operand. | C *= A is equivalent to C = C * A |

/= | Divide AND assignment operator. It divides left operand with the right operand and assign the result to left operand. | C /= A is equivalent to C = C / A |

%= | Modulus AND assignment operator. It takes modulus using two operands and assign the result to left operand. | C %= A is equivalent to C = C % A |

<<= | Left shift AND assignment operator. | C <<= 2 is same as C = C << 2 |

>>= | Right shift AND assignment operator. | C >>= 2 is same as C = C >> 2 |

&= | Bitwise AND assignment operator. | C &= 2 is same as C = C & 2 |

^= | bitwise exclusive OR and assignment operator. | C ^= 2 is same as C = C ^ 2 |

|= | bitwise inclusive OR and assignment operator. | C |= 2 is same as C = C | 2 |

## Miscellaneous Operators

There are few other operators supported by Java Language.

### Conditional Operator ( ? : )

Conditional operator is also known as the **ternary operator**. This operator consists of three operands and is used to evaluate Boolean expressions. The goal of the operator is to decide, which value should be assigned to the variable. The operator is written as −

Following is an example −

**Example**

This will produce the following result −

**Output**

### instanceof Operator

This operator is used only for object reference variables. The operator checks whether the object is of a particular type (class type or interface type). instanceof operator is written as −

( Object reference variable ) instanceof (class/interface type)If the object referred by the variable on the left side of the operator passes the IS-A check for the class/interface type on the right side, then the result will be true. Following is an example −

**Example**

This will produce the following result −

**Output**

This operator will still return true, if the object being compared is the assignment compatible with the type on the right. Following is one more example −

**Example**

This will produce the following result −

**Output**

## Precedence of Java Operators

Operator precedence determines the grouping of terms in an expression. This affects how an expression is evaluated. Certain operators have higher precedence than others; for example, the multiplication operator has higher precedence than the addition operator −

For example, x = 7 + 3 * 2; here x is assigned 13, not 20 because operator * has higher precedence than +, so it first gets multiplied with 3 * 2 and then adds into 7.

Here, operators with the highest precedence appear at the top of the table, those with the lowest appear at the bottom. Within an expression, higher precedence operators will be evaluated first.

Category | Operator | Associativity |
---|---|---|

Postfix | >() [] . (dot operator) | Left toright |

Unary | >++ - - ! ~ | Right to left |

Multiplicative | >* / | Left to right |

Additive | >+ - | Left to right |

Shift | >>> >>> << | Left to right |

Relational | >> >= < <= | Left to right |

Equality | >== != | Left to right |

Bitwise AND | >& | Left to right |

Bitwise XOR | >^ | Left to right |

Bitwise OR | >| | Left to right |

Logical AND | >&& | Left to right |

Logical OR | >|| | Left to right |

Conditional | ?: | Right to left |

Assignment | >= += -= *= /= %= >>= <<= &= ^= |= | Right to left |

## What is Next?

The next chapter will explain about loop control in Java programming. The chapter will describe various types of loops and how these loops can be used in Java program development and for what purposes they are being used.

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## Java Assignment Operators

## Description

Assigning a value to a variable seems straightforward enough; you simply assign the stuff on the right side of the '= 'to the variable on the left. Below statement 1 assigning value 10 to variable x and statement 2 is creating String object called name and assigning value "Amit" to it.

Statement 1: x =10; Statement 2: String name = new String ("Amit");Assignment can be of various types. Let’s discuss each in detail.

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**Primitive Assignment:**

The equal (=) sign is used for assigning a value to a variable. We can assign a primitive variable using a literal or the result of an expression.

int x = 7; // literal assignment int y = x + 2; // assignment with an expression int z = x * y; // assignment with an expression with literal**Primitive Casting**

Casting lets you convert primitive values from one type to another. We need to provide casting when we are trying to assign higher precision primitive to lower precision primitive for example If we try to assign int variable (which is in the range of byte variable) to byte variable then the compiler will throw an exception called "possible loss of precision". Eclipse IDE will suggest the solution as well as shown below. To avoid such problem we should use type casting which will instruct compiler for type conversion.

byte v = (byte) a;For cases where we try to assign smaller container variable to larger container variables we do not need of explicit casting. The compiler will take care of those type conversions. For example, we can assign byte variable or short variable to an int without any explicit casting.

**Assigning Literal that is too large for a variable**

When we try to assign a variable value which is too large (or out of range ) for a primitive variable then the compiler will throw exception “possible loss of precision” if we try to provide explicit cast then the compiler will accept it but narrowed down the value using two’s complement method. Let’s take an example of the byte which has 8-bit storage space and range -128 to 127. In below program we are trying to assign 129 literal value to byte primitive type which is out of range for byte so compiler converted it to -127 using two’s complement method. Refer link for two’s complement calculation (http://en.wikipedia.org/wiki/Two's_complement)

Java Code: Go to the editor

Output:

**Reference variable assignment**

We can assign newly created object to object reference variable as below

String s = new String(“Amit”); Employee e = New Employee();First line will do following things,

- Makes a reference variable named s of type String
- Creates a new String object on the heap memory
- Assigns the newly created String object to the reference variables

You can also assign null to an object reference variable, which simply means the variable is not referring to any object. The below statement creates space for the Employee reference variable (the bit holder for a reference value) but doesn't create an actual Employee object.

Employee a = null;**Compound Assignment Operators**

Sometime we need to modify the same variable value and reassigned it to a same reference variable. Java allows you to combine assignment and addition operators using a shorthand operator. For example, the preceding statement can be written as:

i +=8; //This is same as i = i+8;The += is called the addition assignment operator. Other shorthand operators are shown below table

Operator | Name | Example | Equivalent |
---|---|---|---|

+= | Addition assignment | i+=5; | i=i+5 |

-= | Subtraction assignment | j-=10; | j=j-10; |

*= | Multiplication assignment | k*=2; | k=k*2; |

/= | Division assignment | x/=10; | x=x/10; |

%= | Remainder assignment | a%=4; | a=a%4; |

Below is the sample program explaining assignment operators:

Java Code: Go to the editor

Output:

**Summary **

- Assigning a value to can be straight forward or casting.
- If we assign the value which is out of range of variable type then 2’s complement is assigned.
- Java supports shortcut/compound assignment operator.

**Java Code Editor:**

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