 # C Programming Operators

In this tutorial, you will learn about different operators in C programming with the help of examples.

## Video: Arithmetic Operators in C

An operator is a symbol that operates on a value or a variable. For example: + is an operator to perform addition.

C has a wide range of operators to perform various operations.

## C Arithmetic Operators

An arithmetic operator performs mathematical operations such as addition, subtraction, multiplication, division etc on numerical values (constants and variables).

Operator Meaning of Operator
- subtraction or unary minus
* multiplication
/ division
% remainder after division (modulo division)

### Example 1: Arithmetic Operators

``````// Working of arithmetic operators
#include <stdio.h>
int main()
{
int a = 9,b = 4, c;

c = a+b;
printf("a+b = %d \n",c);
c = a-b;
printf("a-b = %d \n",c);
c = a*b;
printf("a*b = %d \n",c);
c = a/b;
printf("a/b = %d \n",c);
c = a%b;
printf("Remainder when a divided by b = %d \n",c);

return 0;
}``````

Output

```a+b = 13
a-b = 5
a*b = 36
a/b = 2
Remainder when a divided by b=1```

The operators `+`, `-` and `*` computes addition, subtraction, and multiplication respectively as you might have expected.

In normal calculation, `9/4 = 2.25`. However, the output is `2` in the program.

It is because both the variables a and b are integers. Hence, the output is also an integer. The compiler neglects the term after the decimal point and shows answer `2` instead of `2.25`.

The modulo operator `%` computes the remainder. When `a=9` is divided by `b=4`, the remainder is `1`. The `%` operator can only be used with integers.

Suppose `a = 5.0`, `b = 2.0`, `c = 5` and `d = 2`. Then in C programming,

```// Either one of the operands is a floating-point number
a/b = 2.5
a/d = 2.5
c/b = 2.5

// Both operands are integers
c/d = 2```

## C Increment and Decrement Operators

C programming has two operators increment `++` and decrement `--` to change the value of an operand (constant or variable) by 1.

Increment `++` increases the value by 1 whereas decrement `--` decreases the value by 1. These two operators are unary operators, meaning they only operate on a single operand.

### Example 2: Increment and Decrement Operators

``````// Working of increment and decrement operators
#include <stdio.h>
int main()
{
int a = 10, b = 100;
float c = 10.5, d = 100.5;

printf("++a = %d \n", ++a);
printf("--b = %d \n", --b);
printf("++c = %f \n", ++c);
printf("--d = %f \n", --d);

return 0;
}``````

Output

```++a = 11
--b = 99
++c = 11.500000
--d = 99.500000```

Here, the operators `++` and `--` are used as prefixes. These two operators can also be used as postfixes like `a++` and `a--`. Visit this page to learn more about how increment and decrement operators work when used as postfix.

## C Assignment Operators

An assignment operator is used for assigning a value to a variable. The most common assignment operator is `=`

Operator Example Same as
= a = b a = b
+= a += b a = a+b
-= a -= b a = a-b
*= a *= b a = a*b
/= a /= b a = a/b
%= a %= b a = a%b

### Example 3: Assignment Operators

``````// Working of assignment operators
#include <stdio.h>
int main()
{
int a = 5, c;

c = a;      // c is 5
printf("c = %d\n", c);
c += a;     // c is 10
printf("c = %d\n", c);
c -= a;     // c is 5
printf("c = %d\n", c);
c *= a;     // c is 25
printf("c = %d\n", c);
c /= a;     // c is 5
printf("c = %d\n", c);
c %= a;     // c = 0
printf("c = %d\n", c);

return 0;
}``````

Output

```c = 5
c = 10
c = 5
c = 25
c = 5
c = 0```

### C Relational Operators

A relational operator checks the relationship between two operands. If the relation is true, it returns 1; if the relation is false, it returns value 0.

Relational operators are used in decision making and loops.

Operator Meaning of Operator Example
== Equal to `5 == 3` is evaluated to 0
> Greater than `5 > 3` is evaluated to 1
< Less than `5 < 3` is evaluated to 0
!= Not equal to `5 != 3` is evaluated to 1
>= Greater than or equal to `5 >= 3` is evaluated to 1
<= Less than or equal to `5 <= 3` is evaluated to 0

### Example 4: Relational Operators

``````// Working of relational operators
#include <stdio.h>
int main()
{
int a = 5, b = 5, c = 10;

printf("%d == %d is %d \n", a, b, a == b);
printf("%d == %d is %d \n", a, c, a == c);
printf("%d > %d is %d \n", a, b, a > b);
printf("%d > %d is %d \n", a, c, a > c);
printf("%d < %d is %d \n", a, b, a < b);
printf("%d < %d is %d \n", a, c, a < c);
printf("%d != %d is %d \n", a, b, a != b);
printf("%d != %d is %d \n", a, c, a != c);
printf("%d >= %d is %d \n", a, b, a >= b);
printf("%d >= %d is %d \n", a, c, a >= c);
printf("%d <= %d is %d \n", a, b, a <= b);
printf("%d <= %d is %d \n", a, c, a <= c);

return 0;
}``````

Output

```5 == 5 is 1
5 == 10 is 0
5 > 5 is 0
5 > 10 is 0
5 < 5 is 0
5 < 10 is 1
5 != 5 is 0
5 != 10 is 1
5 >= 5 is 1
5 >= 10 is 0
5 <= 5 is 1
5 <= 10 is 1 ```

### C Logical Operators

An expression containing logical operator returns either 0 or 1 depending upon whether expression results true or false. Logical operators are commonly used in decision making in C programming.

Operator Meaning Example
&& Logical AND. True only if all operands are true If c = 5 and d = 2 then, expression `((c==5) && (d>5))` equals to 0.
|| Logical OR. True only if either one operand is true If c = 5 and d = 2 then, expression `((c==5) || (d>5))` equals to 1.
! Logical NOT. True only if the operand is 0 If c = 5 then, expression `!(c==5)` equals to 0.

### Example 5: Logical Operators

``````// Working of logical operators

#include <stdio.h>
int main()
{
int a = 5, b = 5, c = 10, result;

result = (a == b) && (c > b);
printf("(a == b) && (c > b) is %d \n", result);

result = (a == b) && (c < b);
printf("(a == b) && (c < b) is %d \n", result);

result = (a == b) || (c < b);
printf("(a == b) || (c < b) is %d \n", result);

result = (a != b) || (c < b);
printf("(a != b) || (c < b) is %d \n", result);

result = !(a != b);
printf("!(a != b) is %d \n", result);

result = !(a == b);
printf("!(a == b) is %d \n", result);

return 0;
}
``````

Output

```(a == b) && (c > b) is 1
(a == b) && (c < b) is 0
(a == b) || (c < b) is 1
(a != b) || (c < b) is 0
!(a != b) is 1
!(a == b) is 0 ```

Explanation of logical operator program

• `(a == b) && (c > 5)` evaluates to 1 because both operands `(a == b)` and `(c > b)` is 1 (true).
• `(a == b) && (c < b)` evaluates to 0 because operand `(c < b)` is 0 (false).
• `(a == b) || (c < b)` evaluates to 1 because `(a = b)` is 1 (true).
• `(a != b) || (c < b)` evaluates to 0 because both operand `(a != b)` and `(c < b)` are 0 (false).
• `!(a != b)` evaluates to 1 because operand `(a != b)` is 0 (false). Hence, !(a != b) is 1 (true).
• `!(a == b)` evaluates to 0 because `(a == b)` is 1 (true). Hence, `!(a == b)` is 0 (false).

### C Bitwise Operators

During computation, mathematical operations like: addition, subtraction, multiplication, division, etc are converted to bit-level which makes processing faster and saves power.

Bitwise operators are used in C programming to perform bit-level operations.

Operators Meaning of operators
& Bitwise AND
| Bitwise OR
^ Bitwise exclusive OR
~ Bitwise complement
<< Shift left
>> Shift right

## Other Operators

### Comma Operator

Comma operators are used to link related expressions together. For example:

``int a, c = 5, d;``

### The sizeof operator

The `sizeof` is a unary operator that returns the size of data (constants, variables, array, structure, etc).

### Example 6: sizeof Operator

``````#include <stdio.h>
int main()
{
int a;
float b;
double c;
char d;
printf("Size of int=%lu bytes\n",sizeof(a));
printf("Size of float=%lu bytes\n",sizeof(b));
printf("Size of double=%lu bytes\n",sizeof(c));
printf("Size of char=%lu byte\n",sizeof(d));

return 0;
}``````

Output

```Size of int = 4 bytes
Size of float = 4 bytes
Size of double = 8 bytes
Size of char = 1 byte
```

Other operators such as ternary operator `?:`, reference operator `&`, dereference operator `*` and member selection operator `->` will be discussed in later tutorials.