Operators in C programming

Published on : 30th Sep 2021
Operators is an important concept in any programming.
There are three types of operators in C programming. They are Unary, Binary and Ternary.
Arithmetic Operators :
     +, - , *, /, %
Assignment Operator :
     =
Relational Operators :
      <, >, <=, >=, ==, !=
Logical Operators :
      ||, &&, !
Short-circuit Operators :
     || , &&
Bitwise Operators :
     ~, |, &, ^, <<, >>
Compound Assignment Operators or Short-hand Operators :
     +=, -=, *=, /=, %=,  |=, &=, ^=, <<=, >>=
Conditional or Ternary Operator :
     ?    :
Increment and Decrement Operators :
     ++, --
Misc. Operators :
     *, *., []
Let's discuss the operators available in C programming one by one. 
Arithmetic Operators :
Source Code : 
#include <stdio.h>

int main(int argc, char** argv)
{
	int num1 = 10;
	int num2 = 20;
	int add = num1 + num2;
	int sub = num1 - num2;
	int mul = num1 * num2;
	float div = num1 / (float)num2;
	int rem = num2 % num1;
	printf("Addition = %d\n", add);
	printf("Subtraction = %d\n", sub);
	printf("Multiplication = %d\n", mul);
	printf("Division = %f\n", div);
	printf("Remainder = %d\n", rem);
	return 0;
}
Output :
Addition = 30
Subtraction = -10
Multiplication = 200
Division = 0.500000
Remainder = 0
Assignment Operator :
Source Code :
#include <stdio.h>

int main(int argc, char** argv)
{
	int num1 = 10;
	printf("Assigned in num1 is %d.", num1);
	return 0;
}
Output :
Assigned in num1 is 10.
Relational Operators : 
Source Code :  
#include <stdio.h>

int main(int argc, char** argv)
{
	int num1 = 10;
	int num2 = 11;
	printf("Greater than = %d\n", num1 > num2);
	printf("Less than = %d\n", num1 < num2);
	printf("Greater than or equal to = %d\n", num1 >= num2);
	printf("Less than or equal to = %d\n", num1 <= num2);
	printf("Equal to = %d\n", num1 == num2);
	printf("Not equal to = %d\n", num1 != num2);
	return 0;
}
Output :
Greater than = 0
Less than = 1
Greater than or equal to = 0
Less than or equal to = 1
Equal to = 0
Not equal to = 1
Note : Boolean in C programming is represented as 0(false) and 1(true).
Logical Operators :
Source Code : 
#include <stdio.h>

int main(int argc, char** argv)
{
	int num1 = 10;
	int num2 = 11;
	printf("Logical or = %d\n", num1 == 11 || num2 == 11);
	printf("Logical and = %d\n", num1 == 11 && num2 == 11);
	printf("Logical not = %d\n", !num1);
	return 0;
}
Output : 
Logical or = 1
Logical and = 0
Logical not = 0
Explanation :
As num1 is not 11 so control goes to num2 == 11. The expression is true. For that, 1 is printed.
As num1 is not 11 so control doesn't go to num2 == 11 though the expression is true. For that, it is known as short-circuit operator. Hence, 0 is printed.
Any non-zero value is treated as true. Now logical not operator reverses true as false and false as true. Hence, 0 is printed.
Short-circuit Operators :
See the explanation of logical operators.
Bitwise Operators :  
Source Code :
#include <stdio.h>

int main(int argc, char** argv)
{
	int num1 = 10;
	int num2 = 20;
	printf("Bitwise not = %d\n", ~num1);
	printf("Bitwise or = %d\n", num1 | num2);
	printf("Bitwise and = %d\n", num1 & num2);
	printf("Bitwise xor = %d\n", num1 ^ num2);
	printf("Bitwise left shift = %d\n", num1 << 1);
	printf("Bitwise right shift = %d\n", num1 >> 1);
	return 0;
}
Output :
Bitwise not = -11
Bitwise or = 30
Bitwise and = 0
Bitwise xor = 30
Bitwise left shift = 20
Bitwise right shift = 5
Explanation :
~(pronounce as tilde) is 1's complement operator.
We will use binary representation that computer uses.
Number: 0011
1's complement of the number: 1100
Or(|) operations :
op1 op2    Result (op1 | op2)
0      0            0
0      1            1
1      0            1
1      1            1

And(&) operations :
op1 op2    Result (op1 & op2)
0      0            0
0      1            0
1      0            0
1      1            1 

Xor(^) operations :
op1 op2    Result (op1 ^ op2)
0      0            0
0      1            1
1      0            1
1      1            0  

Left Shift operator (<<) shifts one bit to the left. The no. of times shifts, it is multiplied by 2 with the number.  
Number : 10
Number << 1 : 20

Right Shift operator (>>) shifts one bit to the right. The no. of times shifts, it is divided by 2 with the number.  
Number : 10
Number >> 1 : 5 
Compound Assignment Operators or Short-hand Operators : 
Source Code :
#include <stdio.h>

int main(int argc, char** argv)
{
	int num1 = 5;
	int num2 = 20;
	num1 += num2; // num1 = num1 + num2
	printf("Addition = %d\n", num1);
	num1 |= num2; // num1 = num1 | num2
	printf("Bitwise or = %d\n", num1);
	return 0;
}
Output :
Addition = 25
Bitwise or = 29
Conditional or Ternary Operator :
#include <stdio.h>

int main(int argc, char** argv)
{
	int num1 = 5;
	int num2 = 20;
	int big = num1 >= num2 ? num1 : num2;
	printf("Big = %d\n", big);
	return 0;
}
Output :
Big = 20
Explanation :
Syntax: Condition > evaluate if the condition is true : evaluate if the condition is false.
Increment and Decrement Operators : 
Source Code :
#include <stdio.h>

int main(int argc, char** argv)
{
	int val = 0;
	printf("Pre increment = %d\n", ++val);
	printf("Post increment = %d\n", val++);
	printf("Pre decrement = %d\n", --val);
	printf("Post decrement = %d\n", val--);
	return 0;
}
Output :
Pre increment = 1
Post increment = 1
Pre decrement = 1
Post decrement = 1
Explanation :
pre increment or decrement operator :  first increment or decrement then use.
res = ++pre  evaluated as 
pre = pre + 1;
res = pre;

post increment or decrement operator : first use then increment or decrement.
res = post++  evaluated as 
res = post;
post = post + 1; 
Misc. Operators:
We have miscellaneous operators in C. We will learn them when we will progress. 
Example:  [] is subscript operator. * is pointer or value at address operator.