Precedence and Associativity of operator in C

/*Precedence and Associativity of operators in C */

operator precedence determines which operation is performed first in an expression with more than one operators with different precedence.

for example :

2+5*3

in  the above example multiplication operator have high precedence as compare to addition operator so,  multiply will happening first as higher precedence than after addition will happening lower precedence.

2+5*3

2+15

17

/*program to demonstrate precedence of an operator*/

#include <stdio.h>

int main()

{

    int a = 2, b = 5, c = 3, d;

    d = a + b * c; // multiplication have higher precedence as compare to addition operator have lower precedence

    printf("d=%d", d);

    return 0;

}

Output:
d=17

Operators Associativity is used when two operator have same precedence appear in an expression. Associativity can either left to right or right to left.

for example: '*' and '/' have same precedence and their associativity is left to right.

18/3*2

18/3 in above example multiplication operator and division operator have same precedence and associativity left to right so, division operation perform first then after multiplication operation.

18/3*2
6*2
12

/*program to demonstrate associtivity of an operator*/

#include <stdio.h>

int main()

{

    int a = 18, b = 3, c = 2, d;

    d = a / b * c;// division and multiplication have same precedence

    printf("d=%d", d);

    return 0;

}

Output:
d=12

Precedence and associativity of operators

precedence	Operator	Description	Associativity
1	() [] -> .	Function call array subscript arrow operator Dot operator	Left to Right
2	++   – –  +  –  ! ~  (data type)  *  &  sizeof	Increment Decrement Unary plus Unary minus Logical NOT One’s complement Cast operator Indirection Address Size in byte	right-to-left
3	* / %	Multiplication Division modulus	Left to Right
4	+ -	Addition Subtraction	Left to Right
5	<<  >>	Left shift Right shift	Left to Right
6	<  <= >  >=	Less than Less than or equal to Greater than Greater than or equal to	Left to Right
7	== !=	Equal to Not equal to	Left to Right
8	&	Bitwise AND	Left to Right
9	^	Bitwise XOR	Left to Right
10	|	Bitwise OR	Left to Right
11	&&	Logical AND	Left to Right
12	||	Logical OR	Left to Right
13	? :	Ternary operator	right-to-left
14	=  +=  -=  *=  /=  %=  &=  ^=  !=  <<=  >>=	Assignment operator	right-to-left
15	,	Comma operator	Left to Right

 

solve the problems and write the comment

a = 8, b = 4, c = 2, d = 1, e = 5, f = 20

(i) a + b - (c + d) * 3 % e + f / 9

(ii) a % 6 - b / 2 + (c * d - 5) / e * f

Operator quiz for practice