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C

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C Operators

Operators are the symbol which operates on value or a variable. For example: + is a operator to perform addition.

C programming language has wide range of operators which perform various operations. For understanding operators better, we classify these operators in following types according to their operations

Operators in C programming
Arithmetic Operators
Increment and Decrement Operators
Assignment Operators
Relational Operators
Logical Operators
Conditional Operators
Bitwise Operators
Special Operators
Arithmetic Operators

They are used to perform operations of basic mathematics. Following table shows all the arithmetic operators supported by C language. Assume variable named A holds 10 and variable named B holds 20 then:

OperatorDescriptionExample
+Adds two operands A + B will give 30
-Subtracts second operand from the first A - B will give -10
*Multiplies both operands A * B will give 200
/Divides numerator by de-numerator B / A will give 2
%Modulus Operator or Remainder operator returns remainder of an integer division B % A will give 0
++Increments operator increases value of integer by one A++ will give 11
--Decrements operator decreases value of integer by one A-- will give 9
Relational Operators

Relational operators used to check relation between the value of two variable whether they are equal, small, etc. Following table shows all the relational operators supported by C language. Assume a variable named A holds 10 and variable named B holds 20, then:

OperatorDescriptionExample
== Checks if the values of two operands (means value of the variable) are equal or not, if yes then condition becomes true. (A == B) is not true.
!= It also checks if the values of two operands are equal or not, but if values are not equal then condition becomes true (i.e. Opposite of == operator) (A != B) is true.
> Checks if the value of left operand is greater than the value of right operand, if yes then condition becomes true. (A > B) is not true.
< It checks if the value of left operand is less than the value of right operand, if yes then 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 condition becomes true. (A >= B) is not true.
<= It checks if value of the left operand is less than or equal to the value of right operand, if yes then condition becomes true. (A <= B) is true.
Logical Operators

Logical Operators are used for performing operations performed by logical gates, they are mainly used for flow of decision making. Given table shows all the logical operators supported by C language. Assume a variable named A holds 1 and variable named B holds 0, then:

OperatorDescriptionExample
&& Called Logical AND operator. If both the operands are non-zero, then condition becomes true (or it returns true if both conditions are true otherwise false). (A && B) is false.
||Called Logical OR Operator. If any of the two operands is non-zero, then condition becomes true (or it returns true if any one condition or both the conditions are true otherwise false ). (A || B) is true.
!Called Logical NOT Operator. Use to reverses the logical state. If a condition is true then Logical NOT operator will make false and if a condition is false then Logical NOT operator will make true. !(A && B) is true.
Bitwise Operators

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

pqp & qp | qp ^ q
00000
01011
11110
10011

Assume if A = 60; and B = 13; now 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 Bitwise operators supported by C language are listed in the above table. Assume variable A holds value 60 and variable B holds value 13, then:

OperatorDescriptionExample
& Binary AND Operator copies a bit to the result if it exists in both operands. Operation (A & B) will give 12, which is 0000 1100 in binary
| Binary OR Operator copies a bit if it exists in either operand. (A | B) will give 61, which is 0011 1101
^ Binary XOR Operator copies the bit if it is set in one operand but not both. (A ^ B) will give 49, which is 0011 0001
~ Binary Ones Complement Operator is unary and has the effect of 'flipping' bits. (~A ) will give -61, which is 1100 0011 in 2's complement form.
<< Binary Left Shift Operator. The left operands value is moved left by the number of bits specified by the right operand. A << 2 will give 240 which is 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 will give 15 which is 0000 1111
Assignment Operators

Assignment Operator is for assigning a value to the variable. Following assignment operators supported by C language:

OperatorDescriptionExample
=Simple assignment operator, Assigns values from right side operands to left side operand (or simply assigns the value) C = A + B will assign value of A + B into C
+=Add AND assignment operator, It adds right operand value to the left operand value and assign the result to left operand C += A is equivalent to C = C + A
-=Subtract AND assignment operator, It subtracts right operand value from the left operand value and assign the result to left operand C -= A is equivalent to C = C - A
*=Multiply AND assignment operator, It multiplies right operand value with the left operand value and assign the result to left operand C *= A is equivalent to C = C * A
/=Divide AND assignment operator, It divides left operand value with the right operand value and assign the result to left operand C /= A is equivalent to C = C / A
%=Modulus AND assignment operator, It takes modulus using two operand values and assign the result to 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

There are few other important operators supported by C Language. which are following:

OperatorDescriptionExample
sizeof()Returns the size of an variable or data type sizeof(a), where a is character, will return 1.
&It returns the address of memory area where a particular variable is stored.&a; will give actual address of the variable.
*Pointer to a variable(pointer points to the address of a variable).*a; will pointer to a variable.
? :Conditional Expression(It is an abstract morph of if else condition) If Condition is true ? Then value X : Otherwise value Y
Operators Precedence in C

Operator precedence defines order of operator evolution. Operator precedence determines the grouping of terms in an expression. This affects in which order an expression is evaluated. Operators having higher precedence than others is evaluated firstly; for example, the multiplication operator has higher precedence than the addition operator so multiplication take place before addition.

For example x = 7 + 3 * 2; here, x is assigned 13, not 20 because operator * has higher precedence than +, so it first gets multiplied with 3*2 and then adds into 7.

Here, operators with the highest precedence appear at the top of the table, and those with the lowest appear at the bottom. In any expression, higher precedence operators will be evaluated first then lower.

Category  Operator Associativity 
Postfix () [] -> . ++ - -   Left to right 
Unary  + - ! ~ ++ - - (type)* & sizeof  Right to left 
Multiplicative   * / % Left to right 
Additive  + -  Left to right 
Shift   << >>  Left to right 
Relational  < <= > >=  Left to right 
Equality   == !=  Left to right 
Bitwise AND  Left to right 
Bitwise XOR  Left to right 
Bitwise OR  Left to right 
Logical AND &&  Left to right 
Logical OR  ||  Left to right 
Conditional ?:  Right to left 
Assignment  = += -= *= /= %=>>= <<= &= ^= |= Right to left 
Comma  Left to right 


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