Operator Precedence

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Operator Precedence

In Java, Operator Precedence is an evaluation order in which the operators within an expression are evaluated on the priority bases.

In Java, Operator Precedence is an evaluation order in which the operators within an expression are evaluated on the priority bases.

Operator Precedence

     

Operator Precedence :

In Java, Operator Precedence is an evaluation order in which the operators within an expression are evaluated on the priority bases. Operators with a higher precedence are applied before operators with a lower precedence. 
For instance, the expression "4 + 5 * 6 / 3" will be treated as "4 + (5 * (6 / 3))" and 14 is obtained as a result.

When two operators share an operand then operator with the higher precedence gets evaluated first. However, if the operators  have the equal precedence in the same expression then that  expression will be evaluated from left to right except the assignment operators.
For example a = b = c = 15 is treated as a = (b = (c = 15)).

 The table below shows the list of operators that follow the precedence. 

 Operators  Precedence
 array index & parentheses    [ ]  (  ) 
 access object     .
 postfix  expr++  expr--
 unary  ++expr --expr  +expr  -expr  ~  !
 multiplicative  *  /  %
 additive  +  -
 bit shift   <<   >>   >>>
 relational  < >  <=  >=  instanceof
 equality  ==  !=
 bitwise AND  &
 bitwise exclusive OR  ^
 bitwise inclusive OR  |
 logical AND  &&
 logical OR  ||
 ternary  ? :
 assignment  =   +=   -=   *=   /=   %=  &=   ^=  |=    <<=  >>=  >>  >=

Lets see an example that evaluates an arithmetic expression according to the precedence order.

class PrecedenceDemo{
  public static void main(String[] args){
  int a = 6;
  int b = 5;
  int c = 10;
  float rs = 0;
  rs = a + (++b)* ((c / a)* b);
  System.out.println("The result is:" + rs);
  }
}

The expression "a+(++b)*((c/a)*b)" is evaluated from right to left. Its evaluation order depends upon the precedence order of the operators. It is shown below:

(++b)  a + (++b)*((c/a)*b)
(c/a)  a+ (++b)*((c/a)*b)
(c/a)*b  a + (++b)*((c/a)* b)
(++b)*((c/a)*b)  a + (++b)*((c/a)* b)
a+(++b)*((c/a)*b)  a+(++b)*((c/a)*b)

Output of the Program: 

C:\nisha>javac PrecedenceDemo.java

C:\nisha>java PrecedenceDemo
The result is: 42.0

 

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