07. C – Operators

By | October 29, 2020

An operator is a symbol that tells the compiler to perform specific mathematical or logical functions. C language is rich in built-in operators and provides the following types of operators –

We will, in this chapter, look into the way each operator works.

Arithmetic Operators

These are the operators used to perform arithmetic/mathematical operations on operands. Examples: (+, -, *, /, %,++,–). The arithmetic operator is of two types:

  1. Unary Operators: Operators that operate or work with a single operand are unary operators. For example: (++ , –)
  2. Binary Operators: Operators that operate or work with two operands are binary operators. For example: (+ , – , * , /)

The following table shows all the arithmetic operators supported by the C language. Assume variable A holds 10 and variable B holds 20 then

OperatorDescriptionExample
+Adds two operands.A + B = 30
Subtracts second operand from the first.A − B = -10
*Multiplies both operands.A * B = 200
/Divides numerator by de-numerator.B / A = 2
%Modulus Operator and remainder of after an integer division.B % A = 0
++Increment operator increases the integer value by one.A++ = 11
Decrement operator decreases the integer value by one.A– = 9

Relational Operators

The following table shows all the relational operators supported by C. Assume variable A holds 10 and variable B holds 20 then

OperatorDescriptionExample
==Checks if the values of two operands are equal or not. If yes, then the condition becomes true.(A == B) is not true.
!=Checks if the values of two operands are equal or not. If the values are not equal, then the condition becomes true.(A != B) is true.
>Checks if the value of left operand is greater than the value of right operand. If yes, then the condition becomes true.(A > B) is not true.
<Checks if the value of left operand is less than the value of right operand. If yes, then the condition becomes true.(A < B) is true.
>=Checks if the value of left operand is greater than or equal to the value of right operand. If yes, then the condition becomes true.(A >= B) is not true.
<=Checks if the value of left operand is less than or equal to the value of right operand. If yes, then the condition becomes true.(A <= B) is true.

Logical Operators

The following table shows all the logical operators supported by C language. Assume variable A holds 1 and variable B holds 0, then

OperatorDescriptionExample
&&Called Logical AND operator. If both the operands are non-zero, then the condition becomes true.(A && B) is false.
||Called Logical OR Operator. If any of the two operands is non-zero, then the condition becomes true.(A || B) is true.
!Called Logical NOT Operator. It is used to reverse the logical state of its operand. If a condition is true, then Logical NOT operator will make it false.!(A && B) is true.

Bitwise Operators

Bitwise operator works on bits and perform bit-by-bit operation. The truth tables for &, |, and ^ is as follows −

pqp & qp | qp ^ q
00000
01011
11110
10011

Assume A = 60 and B = 13 in binary format, they will be as follows −

A = 0011 1100

B = 0000 1101

—————–

A&B = 0000 1100

A|B = 0011 1101

A^B = 0011 0001

~A = 1100 0011

The following table lists the Bitwise operators supported by C. Assume variable ‘A’ holds 60 and variable ‘B’ holds 13, then −

OperatorDescriptionExample
&Binary AND Operator copies a bit to the result if it exists in both operands.(A & B) = 12, i.e., 0000 1100
|Binary OR Operator copies a bit if it exists in either operand.(A | B) = 61, i.e., 0011 1101
^Binary XOR Operator copies the bit if it is set in one operand but not both.(A ^ B) = 49, i.e., 0011 0001
~Binary One’s Complement Operator is unary and has the effect of ‘flipping’ bits.(~A ) = ~(60), i.e,. -0111101
<<Binary Left Shift Operator. The left operands value is moved left by the number of bits specified by the right operand.A << 2 = 240 i.e., 1111 0000
>>Binary Right Shift Operator. The left operands value is moved right by the number of bits specified by the right operand.A >> 2 = 15 i.e., 0000 1111

Assignment Operators

The following table lists the assignment operators supported by the C language

OperatorDescriptionExample
=Simple assignment operator. Assigns values from right side operands to left side operandC = A + B will assign the value of A + B to C
+=Add AND assignment operator. It adds the right operand to the left operand and assign the result to the left operand.C += A is equivalent to C = C + A
-=Subtract AND assignment operator. It subtracts the right operand from the left operand and assigns the result to the left operand.C -= A is equivalent to C = C – A
*=Multiply AND assignment operator. It multiplies the right operand with the left operand and assigns the result to the left operand.C *= A is equivalent to C = C * A
/=Divide AND assignment operator. It divides the left operand with the right operand and assigns the result to the left operand.C /= A is equivalent to C = C / A
%=Modulus AND assignment operator. It takes modulus using two operands and assigns the result to the left operand.C %= A is equivalent to C = C % A
<<=Left shift AND assignment operator.C <<= 2 is same as C = C << 2
>>=Right shift AND assignment operator.C >>= 2 is same as C = C >> 2
&=Bitwise AND assignment operator.C &= 2 is same as C = C & 2
^=Bitwise exclusive OR and assignment operator.C ^= 2 is same as C = C ^ 2
|=Bitwise inclusive OR and assignment operator.C |= 2 is same as C = C | 2

Misc Operators ↦ sizeof & ternary

Besides the operators discussed above, there are a few other important operators including sizeof and ? : supported by the C Language.

OperatorDescriptionExample
sizeof()Returns the size of a variable.sizeof(a), where a is integer, will return 4.
&Returns the address of a variable.&a; returns the actual address of the variable.
*Pointer to a variable.*a;
? :Conditional Expression.If Condition is true ? then value X : otherwise value Y

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