C Programming Tutorial
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C Operators

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


Operators

C offers us a wide variety of operators that we can use to operate on data.

In C language, operators is a symbol which is used to perform a specific mathematical or logical functions.
In particular, we can identify various groups of operators:

Types of Operators in C language

  1. Arithmetic Operators
  2. Increment and Decrement Operators
  3. Assignment Operators
  4. Relational Operators
  5. Logical Operators
  6. Bitwise Operators
  7. Other Operators

Arithmetic Operators

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

Assume variable A = 10 and variable B = 5 in the examples of table given below :

Operator Meaning of Operator Example
+ Add two operands A + B = 15
Subtract second operand from the first operand. A – B = 5
* Multiplies both operands A * B = 50
/ Divides numerator by denumerator A / B = 2
% Give remainder after division A % B = 0

Example : Arithmetic Operators

#include <stdio.h>
int main(){
  int a = 10, b = 6, c;
  c = a + b;
  printf("a + b = %d \n", c);  // Addition Operator
  c = a - b;
  printf("a - b = %d \n", c); // Subtraction Operator
  c = a * b;
  printf("a * b = %d \n", c); // Multiplication Operator
  c = a / b;
  printf("a / b = %d \n", c); // Division Operator
  c = a % b;
  printf("Remainder when a divided by b = %d \n", c); // Modulus
Operator

  return 0;
}

Output

a + b = 16 
a - b = 4
a * b = 60
a / b = 1
a % b = 4

In the above example,
we observed that 10 /6 = 1 but in normal calculation 10 / 6 = 1.67 while the output in the program is 1. 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 1 instead of 1.67.

Note : The Modulus operator % can only be used with integers.


Increment and Decrement Operators

In C programming, Increment and decrement operators are used to change the value of operand by 1 .

Increment operator ++ increase the value of operand by 1 .
Decrement operator  decrease the value of operand by 1 .

Note : Increment and Decrement operator are unary operator i.e. they can only be used/operate in a single operand.
These operators can be used as suffix and prefix both.

Example : Increment and Decrement Operators


#include <stdio.h>
int main(){
  int a = 5, b = 100;
  float c = 5.3, d = 100.8;
  printf("++a = %d \n", ++a);
  printf("b++ = %d \n", b++);
  printf("--c = %f \n", --c);
  printf("d-- = %f \n", d--);
  return 0;
}

Output

++a is 6 
b++ is 100
--c is 4.300000
d-- is 100.800000

++ and — operator as prefix and postfix

In the above example,
++ operator is used as prefix with variable a i.e. the value of variable a is incremented by 1 then, it returns the value.
++ operator is used as postfix with variable b i.e. the original value of variable a is returned first then, the value of b is incremented by 1.
 operator is used as prefix with variable c i.e. the value of variable c is decremented by 1 then, it returns the value.
 operator is used as postfix with variable d i.e. the original value of variable d is returned first then, the value of d is incremented by 1.


Assignment Operators

The assignment operators are used for assigning a value to a variable.

Operator Example Same as
= 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 : Assignment Operators

#include <stdio.h>
int main(){
  int a = 10, b;
  b = a; // Here, b is 10
  printf("b = %d\n", b);
  b += a; // Here, b is 20
  printf("b = %d\n", b);
  b -= a; // Here, b is 10
  printf("b = %d\n", b);
  b *= a; // Here, b is 100
  printf("b = %d\n", b);
  b /= a; // Here, b is 10
  printf("b = %d\n", b);
  b %= a; // Here, b = 0
  printf("b = %d\n", b);
  return 0;
}

Output

b = 10
b = 20
b = 10
b = 100
b = 10
b = 0

Relational Operators

Relational operators are used to check/define the relationship between two entities. If the relation is true, it return 1; if the relation is false, it return 0.

Note : Relational operators are generally used in loops and decision making.

Now, Assume a = 5 for examples in the table given below :

Operator Meaning of Operator Example
Operator Meaning of operator Example
== Equal to a == 5
> Greater than a > 2
< Less than a < 8
!= Not equal to a != 4
>= Greater than or equal to a >= 1
<= Less than or equal to a <= 6

Example : Relational Operators

#include <stdio.h>
int main(){
  int a = 10, 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

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

Logical Operators

Logical operators are used to make decision (True or False) depending on the given expression.
These operators are commonly used in decision making in C programming.

Operator Meaning Example
Operator Name Meaning
&& Logical AND True only if all the operands are True
|| Logical OR True only of either one operand is true
! Logical NOT True only if the operand is 0

Example : 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

Bitwise Operators

Bitwise operators are special operator set provided in C programming. They are used to convert operands to bit level for basic computation which makes processing faster.

Note :Bitwise Operators are very helpful in programming where we have limited amount of memory and want to run program faster.

Operators Meaning of operators Working
& Bitwise AND Give result 1 (true) if both bits are 1 (true)
| Bitwise OR Give result 1 (true) if any of the two bits is 1 (true)
^ Bitwise XOR Give result 1 (true) if the two bits are different
<< Left Shift Left shifts the bits of the first operand,
the second operand decides the number of places to shift
>> Right Shift Right shifts the bit of the first operand,
the second operand decides the number of places to shift
~ Bitwise NOT Invert all bits of operand

Example : Bitwise Operator

#include <stdio.h>
int main()
{
  unsigned char a = 5, b = 9;
  printf("a & b = %d \n", a & b);
  printf("a | b = %d \n", a | b);
  printf("a ^ b = %d \n", a ^ b);
  printf("~a = %d \n",a = ~a);
  printf("b << 1 = %d \n", b << 1);
  printf("b >> 1 = %d \n", b >> 1);
  return 0;
}

Output

a & b = 1 
a | b = 13
a ^ b = 12
~a = 250
b << 1 = 18
b >> 1 = 4

To know more about Bitwise operators Click here.


Other Operators

The ternary operator

The ternary operator is the only operator in C that works with 3 operands, and it’s a short way to express conditionals.

This is how it looks:

condition ? expression : expression

Example:

a ? b : c

If a is evaluated to true, then the b statement is executed, otherwise c is.

The ternary operator is functionality-wise same as an if/else conditional, except it is shorter to express and it can be inlined into an expression.


Comma Operator

Comma operator is used to link related expressions together or seperate two operands. For example:

int a = 2, c = 3, d = 4;

The sizeof operator

The sizeof operator is the unary operator in C used to compute the size of its operand i.e. it return the size of a variable.

In simple words, the sizeof operator returns the size of the operand you pass. You can pass a variable, or even a type.

Example : 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

Note : The size of data types are different in different systems.

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