Following are the bitwise operators available in C. They may be applied only to integral types like int, char, short and long.

The bitwise AND operator is used to mask off bits.

The bitwise OR operator is used to set the bits.

The bitwise exclusive OR operator sets the bits if both the bits are different

The left shift operator is used to shift the left operand by as many bits as specified by the right operand provided it is a positive integer. As the operand gets shifted to the left, the rightmost bits are filled with 0.

The right shift operator is used to shift the left operand by as many bits as specified by the right operand provided it is a positive integer. As the operand gets shifted to the right, the leftmost bits are filled with 0.

Note that this is in case of unsigned numbers. In case of signed numbers, the results can vary.

Related Posts:

• Operators
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Tags: C, operators, variables

Arithmetic Operators

In C programming, we have the following arithmetic operators:

+                                             Addition

-                                              Subtraction

*                                             Multiplication

/                                             Division

%                                            Modulo

So,

int a = 10;

int b = 5;

int c = 0;

c = a + b; /* c=15 */

c = a – b; /* c=5 */

c = a * b; /*c=50 */

c = a / b; /* c=2 */

c = a % b; /* c=0 */ /* by mod we get the remained of a divided by b */

Each of the above statements are called expressions in C. Every expression is supposed to be terminated by a ; else the compiler will complain. Expressions consist of operands and operators and they produce a result.

Ex: c = a + b /* Here ‘a’ and ‘b’ are operands, ‘+’ is the operator and the result is placed in ‘c’ */

Relational Operators

Following are the relational operators in C programming.

<                                                        Less than

>                                                        Greater than

<=                                                     Less than or equal to

>=                                                    Greater than or equal to

==                                                     Equal to

!=                                                       Not equal to

Hence,

int a = 10;

int b = 5;

int c = 0;

int d = 5;


c = (a < b) /* c=0 */

c = (a > b) /* c=1 */

c = (a <= d) /*c=0*/

c= (b >= d) /*c=1*/

c = (b == d) /*c=1*/

c = (b != d) /*c=0*/

So as it can be seen from the examples above, the result of relational operators will be either 1 or 0 (also know as True or False). Relational operators and Logical Operators (given below) are very useful when we want to check conditions in a program.

Ex: if (water_level >= danger_level) printf(“ALERT”);

Note that programmers often get bugs due to the improper use of ‘=’ instead of ‘==’.

int a = 3;

int b = 9;

if (a = b)   /* MISTAKE: Here a is assigned value of b. INSTEAD WE SHOULD USE (a == b).

printf(“TRUE”);

Logical Operators

The operators && (AND) and || (OR) are known as logical operators. They are binary operators as well i.e they need two operands to function. Operands are evaluated from left to right. && evaluation stops at the first FALSE operand. || evaluation stops at the first TRUE operand.

Note: We can have expressions in place of operands.

if (a < b) && (c < d) || (p < q)

printf(“OK);

&& has higher precedence than ||. If (a<b) is FALSE then we get no print, the statement doesn’t go forward and check for the (c<d) || (p <q)

Increment and Decrement Operators

We have the operators ‘++’ and ‘–’ known as increment and decrement operators.

Ex:

n = n + 1 can be replaced by n++

n = n – 1 can be replaced by n–

Also the increment and decrement operators can be used as prefix or postfix to the variable. Means we can either use n++ or ++n. Both result in the increment of n. The difference comes to light below:

c = n++; /* if n = 5, then after this execution, n = 6 and c = 5 as first n is assigned to c and then incremented*/

c = ++n; /* if n =5, then after this execution, n = 6 and c = 6 as n is first incremented and then assigned to c*/

Increment and decrement operators are useful because compilers can produce optimized code for them.

This seems like a long post already In the next post, will mention something about bitwise operators.

Related Posts:

• Bitwise Operators
• Register and volatile in C programs
• Static variables and functions
• External variables and functions
• Variables in C

Tags: C, operators, variables