Misc. Operators
Besides the operators discussed above, there are a few other important operators including sizeof and ? : supported by the C Language.
| Operator | Description | Example |
|---|---|---|
| sizeof() | Returns the size of a variable. | sizeof(a), where a is integer, will return 4. |
| & | Returns the address of a variable. | &a; returns the actual address of the variable. |
| * | Pointer to a variable. | *a; |
| ? : | Conditional Expression. | If Condition is true ? then value X : otherwise value Y |
#include <stdio.h>
main() {
int a = 4;
short b;
double c;
int* ptr;
/* example of sizeof operator */
printf("Line 1 - Size of variable a = %d\n", sizeof(a) );
printf("Line 2 - Size of variable b = %d\n", sizeof(b) );
printf("Line 3 - Size of variable c= %d\n", sizeof(c) );
/* example of & and * operators */
ptr = &a; /* 'ptr' now contains the address of 'a'*/
printf("value of a is %d\n", a);
printf("*ptr is %d.\n", *ptr);
/* example of ternary operator */
a = 10;
b = (a == 1) ? 20: 30;
printf( "Value of b is %d\n", b );
b = (a == 10) ? 20: 30;
printf( "Value of b is %d\n", b );
}
Output
Line 1 - Size of variable a = 4 Line 2 - Size of variable b = 2 Line 3 - Size of variable c= 8 value of a is 4 *ptr is 4. Value of b is 30 Value of b is 20
Operators Precedence 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 |
