C programming has various operators to perform tasks including arithmetic, conditional and bitwise operations. You will learn about various C operators and how to use them in this tutorial.

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

C programming has wide range of operators to perform various operations. For better understanding of operators, these operators can be classified as:

Operators in C programming |
---|

Arithmetic Operators |

Increment and Decrement Operators |

Assignment Operators |

Relational Operators |

Logical Operators |

Conditional Operators |

Bitwise Operators |

Special Operators |

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

Operator | Meaning of Operator |
---|---|

+ | addition or unary plus |

- | subtraction or unary minus |

* | multiplication |

/ | division |

% | remainder after division( modulo division) |

```
// C Program to demonstrate the 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 variables a and b are integers. Hence, the output is also an integer. The compiler neglects the term after 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, a/b = 2.5 // Because both operands are floating-point variables a/d = 2.5 // Because one operand is floating-point variable c/b = 2.5 // Because one operand is floating-point variable c/d = 2 // Because both operands are integers

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.

```
// C Program to demonstrate the 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 prefix. These two operators can also be used as postfix like `a++`

and `a--`

. Visit this page to learn more on how increment and decrement operators work when used as postfix.

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 |

```
// C Program to demonstrate the working of assignment operators
#include <stdio.h>
int main()
{
int a = 5, c;
c = a;
printf("c = %d \n", c);
c += a; // c = c+a
printf("c = %d \n", c);
c -= a; // c = c-a
printf("c = %d \n", c);
c *= a; // c = c*a
printf("c = %d \n", c);
c /= a; // c = c/a
printf("c = %d \n", c);
c %= a; // c = c%a
printf("c = %d \n", c);
return 0;
}
```

**Output**

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

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 returns 0 |

> | Greater than | 5 > 3 returns 1 |

< | Less than | 5 < 3 returns 0 |

!= | Not equal to | 5 != 3 returns 1 |

>= | Greater than or equal to | 5 >= 3 returns 1 |

<= | Less than or equal to | 5 <= 3 return 0 |

```
// C Program to demonstrate the working of arithmetic operators
#include <stdio.h>
int main()
{
int a = 5, b = 5, c = 10;
printf("%d == %d = %d \n", a, b, a == b); // true
printf("%d == %d = %d \n", a, c, a == c); // false
printf("%d > %d = %d \n", a, b, a > b); //false
printf("%d > %d = %d \n", a, c, a > c); //false
printf("%d < %d = %d \n", a, b, a < b); //false
printf("%d < %d = %d \n", a, c, a < c); //true
printf("%d != %d = %d \n", a, b, a != b); //false
printf("%d != %d = %d \n", a, c, a != c); //true
printf("%d >= %d = %d \n", a, b, a >= b); //true
printf("%d >= %d = %d \n", a, c, a >= c); //false
printf("%d <= %d = %d \n", a, b, a <= b); //true
printf("%d <= %d = %d \n", a, c, a <= c); //true
return 0;
}
```

**Output**

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

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 of Operator | Example |
---|---|---|

&& | Logial 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. |

```
// C Program to demonstrate the 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) equals to %d \n", result);
result = (a == b) && (c < b);
printf("(a == b) && (c < b) equals to %d \n", result);
result = (a == b) || (c < b);
printf("(a == b) || (c < b) equals to %d \n", result);
result = (a != b) || (c < b);
printf("(a != b) || (c < b) equals to %d \n", result);
result = !(a != b);
printf("!(a == b) equals to %d \n", result);
result = !(a == b);
printf("!(a == b) equals to %d \n", result);
return 0;
}
```

**Output**

(a == b) && (c > b) equals to 1 (a == b) && (c < b) equals to 0 (a == b) || (c < b) equals to 1 (a != b) || (c < b) equals to 0 !(a != b) equals to 1 !(a == b) equals to 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).

During computation, mathematical operations like: addition, subtraction, addition and division 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 |

Visit bitwise operator in C to learn more.

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

int a, c = 5, d;

The `sizeof`

is an unary operator which returns the size of data (constant, variables, array, structure etc).

```
#include <stdio.h>
int main()
{
int a, e[10];
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));
printf("Size of integer type array having 10 elements = %lu bytes\n", sizeof(e));
return 0;
}
```

**Output**

Size of int = 4 bytes Size of float = 4 bytes Size of double = 8 bytes Size of char = 1 byte Size of integer type array having 10 elements = 40 bytes

A conditional operator is a ternary operator, that is, it works on 3 operands.

conditionalExpression ? expression1 : expression2

The conditional operator works as follows:

- The first expression conditionalExpression is evaluated first. This expression evaluates to 1 if it's true and evaluates to 0 if it's false.
- If
`conditionalExpression`is true,`expression1`is evaluated. - If
`conditionalExpression`is false,`expression2`is evaluated.

```
#include <stdio.h>
int main(){
char February;
int days;
printf("If this year is leap year, enter 1. If not enter any integer: ");
scanf("%c",&February);
// If test condition (February == 'l') is true, days equal to 29.
// If test condition (February =='l') is false, days equal to 28.
days = (February == '1') ? 29 : 28;
printf("Number of days in February = %d",days);
return 0;
}
```

**Output**

If this year is leap year, enter 1. If not enter any integer: 1 Number of days in February = 29

Other operators such as & (reference operator), * (dereference operator) and -> (member selection) operator will be discussed in C pointers.