Precedence of operators
In C, operator precedence determines the order in which operators are evaluated in an expression. Operators with higher precedence are evaluated before operators with lower precedence. Here’s a list of operators in C, organized by their precedence from highest to lowest:
1. Postfix Operators
expr++(Post-increment)expr--(Post-decrement)
2. Unary Operators
++expr(Pre-increment)--expr(Pre-decrement)+(Unary plus)-(Unary minus)!(Logical NOT)~(Bitwise NOT)&(Address of)*(Dereference)
3. Multiplicative Operators
*(Multiplication)/(Division)%(Modulus)
4. Additive Operators
+(Addition)-(Subtraction)
5. Shift Operators
<<(Left shift)>>(Right shift)
6. Relational Operators
<(Less than)<=(Less than or equal to)>(Greater than)>=(Greater than or equal to)
7. Equality Operators
==(Equal to)!=(Not equal to)
8. Bitwise AND Operator
&(Bitwise AND)
9. Bitwise XOR Operator
^(Bitwise XOR)
10. Bitwise OR Operator
|(Bitwise OR)
11. Logical AND Operator
&&(Logical AND)
12. Logical OR Operator
||(Logical OR)
13. Conditional (Ternary) Operator
? :(Ternary)
14. Assignment Operators
=(Simple assignment)+=,-=,*=,/=,%=,&=,|=,^=,<<=,>>=(Compound assignments)
15. Comma Operator
,(Comma)
Example to Demonstrate Precedence
Here’s a small example illustrating operator precedence:
#include <stdio.h>
int main() {
int a = 5, b = 10, c;
// Example of precedence
c = a + b * 2; // b * 2 is evaluated first
printf(“Result: %d\n”, c); // Output: 25 (5 + 20)
c = (a + b) * 2; // Parentheses change precedence
printf(“Result: %d\n”, c); // Output: 30 (15 * 2)
c = a < b && a > 0; // Both comparisons are evaluated
printf(“Result: %d\n”, c); // Output: 1 (true)
return 0;
}
- Parentheses: You can change the order of evaluation by using parentheses. They have the highest precedence.
- Associativity: Operators with the same precedence are evaluated based on their associativity, which can be left-to-right or right-to-left. For instance, assignment operators are right-to-left, while most arithmetic and relational operators are left-to-right.