by Dinesh Thakur

The assignment operator (=) is the most commonly used binary operator in Java. It evaluates the operand on the tight hand side and then assigns the resulting value to a variable on the left hand side. The right operand can be a variable, constant, function call or expression. The type of right operand must be type compatible with the left operand. The general form of representing assignment operator is

                       Variable = expression/constant/function call

                       a = 3; //constant

                       x = y + 10; //expression

In the first case, a literal value 3 is stored in the memory location allocated to variable a. In the second case, the value of expression y+ 10is evaluated and then stored in memory allocated to

variable x.

Consider a statement x = y = z = 3;

Such type of assignment statement in which a single value is given to a number of variables is called multiple assignment statement i.e. value 3 is assigned to the variables x, y and z. The assignment operator (=) has a right to left associatively, so the above expression is interpreted as

(x = (y = (z = 3)));

Here, first the value 3 is assigned to z, then value stored in z is assigned to y and then finally y is assigned to x. Now let us consider a statement

x = 3 = 5;

This type of statement is invalid assignment statement and it will generate an error.

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There is another kind of assignment statement which combines a simple assignment operator with five arithmetic binary operators and six bitwise operators. This type of operator is known as compound assignment operator. The general syntax of compound assignment operator IS

                 Variable operator= expression/constant/function call

For example: Suppose i is a variable of type int then the statement,

i += 5;

will add the literal 5 to the variable i and store the result back into the variable i. The various compound assignment operators and their effect are as shown in table

Operator

Usage

Effect

+=

-=

*=

/=

%=

&=

|=

^=

<<=

>>=

>>>=

a+=b;

a-=b;

a*=b;

a/=b;

a%=b;

a&=b;

a|=b;

a^=b;

a<<=b;

a>>=b;

a>>>=b;

a=a+b;

a=a-b;

a=a*b;

a=a/b;

 a=a%b;

a=a&b;

a=a|b;

a=a^b;

 a=a<<b;

 a=a>>b;

    a=a>>>b;

Such operator makes the statement concise so they are also called shorthand assignment operator. The expression a = a+b is almost same as that of a += b but the mainadvantage of shorthand assignment operator is that the operand is that the operand on the left handside of the assignment is evaluated only once. The assignment operators have the lowestprecedence as compared to other operators. Only one variable is allowed on the left hand sideof the expression. Therefore a=x*y is valid and m*n=l is invalid.

It is to be kept in mind that assignment operator (=) and equality operator (= =) are different. The assignment operator is used to assign a value to a variable whereas the equality operator used to compare two operands. These operators cannot be used in place of each other. The assignment operator( =) has lower precedence than arithmetic, relational, bitwise, and logical operators.

Java Example to implement assignment operations
import java.util. *;
class AssignmentOperator
{
                  public static void main(String args[])
         {
                    int X=12, Y=13, Z=16;
                    System.out.println("The Assignment Value is : ");
                    X+=2;
                    Y-=2;
                    Z*=2;
                    System.out.println("The Value of X is : " +X);
                    System.out.println("The Value of Y is : " +Y);
                    System.out.println("The Value of Z is : " +Z);
          }
}

Java Example to implement assignment operations

Java Example to perform assignment operations using Scanner Class.
import java.util. *;
class AssignmentOperator
{
                  public static void main(String args[])
         {
                    int X,Y;
                    Scanner scan=new Scanner(System.in);
                    System.out.print("Enter the Value of X : ");
                    X=scan.nextInt();
                    System.out.print("Enter the Value of b : ");
                    Y=scan.nextInt();
                    System.out.println("X += 6 : "+(X+=6));
                    System.out.println("X -= 4 : "+(X-=4));
                    System. out. println("Y *= 4 : "+(Y*=4));
                    System. out. println("Y /= 6 : " +(Y/=6));
          }
}

Java Example to perform assignment operations using Scanner Class.