Operator Precedence and Associativity in C


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

For example, x = 7 + 3 * 2; here, x is assigned 13, not 20 because operator * has a 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 () [] -> . ++ - -  Left to right 
Unary + - ! ~ ++ - - (type)* & sizeof 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 
Comma Left to right 

Example Code

#include <stdio.h>
main() {
   int a = 20;
   int b = 10;
   int c = 15;
   int d = 5;
   int e;
   e = (a + b) * c / d; // ( 30 * 15 ) / 5
   printf("Value of (a + b) * c / d is : %d\n", e );
   e = ((a + b) * c) / d; // (30 * 15 ) / 5
   printf("Value of ((a + b) * c) / d is : %d\n" , e );
   e = (a + b) * (c / d); // (30) * (15/5)
   printf("Value of (a + b) * (c / d) is : %d\n", e );
   e = a + (b * c) / d; // 20 + (150/5)
   printf("Value of a + (b * c) / d is : %d\n" , e );
   return 0;
}

Output

Value of (a + b) * c / d is : 90
Value of ((a + b) * c) / d is : 90
Value of (a + b) * (c / d) is : 90
Value of a + (b * c) / d is : 50

Updated on: 30-Jul-2019

10K+ Views

Kickstart Your Career

Get certified by completing the course

Get Started
Advertisements