C  Operators
An operator is a symbol that tells the compiler to perform specific mathematical or logical manipulations. C language is rich in builtin operators and provides the following types of operators:

Arithmetic Operators

Relational Operators

Logical Operators

Bitwise Operators

Assignment Operators

Misc Operators
This tutorial will explain the arithmetic, relational, logical, bitwise, assignment and other operators one by one.
Arithmetic Operators
Following table shows all the arithmetic operators supported by C language. Assume variable A holds 10 and variable B holds 20 then:
Operator  Description  Example 

+  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 denumerator  B / A will give 2 
%  Modulus Operator and remainder of after an integer division  B % A will give 0 
++  Increments operator increases integer value by one  A++ will give 11 
  Decrements operator decreases integer value by one  A will give 9 
Relational Operators
Following table shows all the relational operators supported by C language. Assume variable A holds 10 and variable B holds 20, then:
Operator  Description  Example 

==  Checks if the values of two operands are equal or not, if yes then condition becomes true.  (A == B) is not true. 
!=  Checks if the values of two operands are equal or not, if values are not equal then 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 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 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. 
<=  Checks if the value of 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
Following table shows all the logical operators supported by C language. Assume variable A holds 1 and variable B holds 0, then:
Operator  Description  Example 

&&  Called Logical AND operator. If both the operands are nonzero, then condition becomes true.  (A && B) is false. 
  Called Logical OR Operator. If any of the two operands is nonzero, then condition becomes true  (A  B) is true. 
!  Called Logical NOT Operator. Use to reverses the logical state of its operand. If a condition is true then Logical NOT operator will make false.  !(A && B) is true. 
Bitwise Operators
Bitwise operator works on bits and perform bitbybit operation. The truth tables for &, , and ^ are as follows:
p  q  p & q  p  q  p ^ q 

0  0  0  0  0 
0  1  0  1  1 
1  1  1  1  0 
1  0  0  1  1 
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
AB = 0011 1101
A^B = 0011 0001
~A = 1100 0011
The Bitwise operators supported by C language are listed in the following table. Assume variable A holds 60 and variable B holds 13, then:
Operator  Description  Example 

&  Binary AND Operator copies a bit to the result if it exists in both operands.  (A & B) will give 12, which is 0000 1100 
  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
There are following assignment operators supported by C language:
Operator  Description  Example 

=  Simple assignment operator, Assigns values from right side operands to left side operand  C = A + B will assign value of A + B into C 
+=  Add AND assignment operator, It adds right operand to the left operand and assign the result to left operand  C += A is equivalent to C = C + A 
=  Subtract AND assignment operator, It subtracts right operand from the left operand and assign the result to left operand  C = A is equivalent to C = C  A 
*=  Multiply AND assignment operator, It multiplies right operand with the left operand and assign the result to left operand  C *= A is equivalent to C = C * A 
/=  Divide AND assignment operator, It divides left operand with the right operand and assign the result to left operand  C /= A is equivalent to C = C / A 
%=  Modulus AND assignment operator, It takes modulus using two operands 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 â†¦ sizeof & ternary
There are few other important operators including sizeof and ? : supported by C Language.
Operator  Description  Example 

sizeof()  Returns the size of an variable.  sizeof(a), where a is integer, will return 4. 
&  Returns the address of an variable.  &a; will give actual address of the variable. 
*  Pointer to a variable.  *a; will pointer to a variable. 
? :  Conditional Expression  If Condition is true ? Then value X : Otherwise value Y 
Operators Precedence in C
Operator precedence determines the grouping of terms in an expression. This affects how an expression is evaluated. Certain operators have higher precedence than others; for example, the multiplication operator has higher precedence than the addition operator.
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, those with the lowest appear at the bottom. Within an expression, higher precedence operators will be evaluated first.
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 
Source: www.tutorialspoint.com