Operators in C Programming

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Expression :

• An expression is anything which evaluates to something.
• Expressions are combinations of operators and operands.

Operator :

Operators are special symbols that perform specific operations on one, two, or three operands, and then return a result.

Operator's Categories:

1. Unary : A unary operator is an operator, which operates on one operand.
2. Binary : A binary operator is an operator, which operates on two operands.
3. Ternary : A ternary operator is an operator, which operates on three operands.

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TYPES OF OPERATOR :-

1. Arithmetic Operator
   [ +, -, *, /, % ]

2. Assignment Operator
   [ =, +=, -=, *=, /=, %= etc...]

3. Increment / Decrement Operator
   [ ++, -- ]

4. Relational Operator
   [ >, <, >=, <=, !=, == ]

5. Logical Operator
   [ &&, ||, ! ]

6. Bitwise Operator
   [ &, |, ^, ~ ]

7. Conditional Operator
   [ ? : ]

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1 . Arithmetic Operator :

Arithmetic operator in C behaves as one would expect

Operator	Example
+ ( Addition )	4+x+5+y
- ( Subtraction )	4-x-5-y
* ( Multiplication )	4*x*5
/ ( Division )	50/x
% ( Modulus ) Divides left-hand operand by right-hand operand and returns remainder.	9%4 result = 1

Compound expression:

      3*x+5-7
      principle + (principle + interest)

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2 . Assignment Operator

• The assignment operator has the lowest precedence of all operator.
• It is always evaluated last.
• Assignment can be used to assign the value of an expression to a variable.
• In assignment, the previous value of the variable is overwritten by the value of the expression.
  variable = expression Example:
  x = x+10
  etaInSecond = distance/speedOfLight;

1. Add Assignment +=
int a = 20;
//add 5 to a
a += 5; similar to  a = a+5;
printf("%d",a);

[OUTPUT : 25]
-----------------------------
2. Multiply Assignment *=
int a = 20;
//multiply 5 to a
a *= 5; similar to a = a*5;
printf("%d",a);

[OUTPUT : 100]
-----------------------------
Similarly, we have
-=, ;/=, %=, <<=, >>=, &=, ^=, |=

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3 . Increment (++) / Decrement (--) Operator

• These operators are used to increment or decrement the variables's value by 1.
• They are unary operator.
• Increment / Decrement operators are used in two ways:
  Post-fix notation : var++ or var--
  Pre-fix notation   : ++var or --var

Post-fix notation
When post-fix notation is used, the result is evaluated first and then the operation (inc / dec) is performed.
Pre-fix notation
When pre-fix notation is used, the operation (inc / dec) is performed first then the result is evaluated.
e.g.

// x initialized to 5
int x = 5; 
int y = x++; (postfix)
//y assigned the value of x
//x is incremented 
[RESULT : x = 6, y = 5]
---------------------------
int z = ++x; (prefix)
//x is incremented
//a assigned the value of x
[RESULT : x = 6, z = 6]
            

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4 . Relational Operator

Relation Operators are used to compare two values. Relational expression always evaluates result as boolean either true ( 1 ) or false ( 0 ).

1. Greater Than: >
int a = 5, b = 10;
( a > b )

[Result: 0]
-----------------
2. Less Than: < 
int a = 5, b = 10;
( a < b )

[Result: 1]
-----------------
3. Equal To: ==
int a = 5, b = 5;
( a == b )

[Result: 1]
------------------
4. Not Equal To: !=
int a = 5, b = 2
( a != b )

[Result: 1]
--------------------
5.Greater Than Equal: >=
int a = 10, b = 5;
( a >= b )

[Result: 1]
-----------------
6.Less Than Equal: <= 
int a = 10, b = 5;
( a <= b )

[Result: 0]

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5 . Logical Operator

Logical Expression
An expression whose value is a boolean type ( true ( 1 ) or false ( 0 ) ).

Logical operators are used when we want to compare more than one relation at a time.

Logical operators:

1. Logical AND ( && ):
   exp1 && exp2
   Logical AND true when both expressions are true.
   Logical AND false when one of the expression is false.
   Truth Table:

   Exp1	Exp2	Result
   true	true	true
   true	false	false
   false	true	false
   false	false	false

2. Logical OR ( || ):
   exp1 || exp2
   Logical OR true when one of the expression is true.
   Logical OR false when when both expressions are false.
   Truth Table:

   Exp1	Exp2	Result
   true	true	true
   true	false	true
   false	true	true
   false	false	false

3. Logical NOT ( ! )
   !expr
   It flips the result.
   Logical Not is true when the expression is false.
   Logical NOT is false when the expression is true.
   Truth Table:

   Expr	Result
   true	false
   false	true

Example:

1. Logical AND ( && ) 
int x = 6;
int b = (x > 5)&&(x < 10);
printf("%d", b );

[OUTPUT: 1]

int x = 6;
int b = (x > 5)&&(x !=6);
printf("%d", b );

[OUTPUT: 0]
-------------------------
2. Logical OR ( || ) 
int x = 6;
int b = (x > 5)||(x !=6);
printf("%d", b );

[OUTPUT: 1]
-------------------------
3. Logical NOT ( ! ) 
int x = 6;
int b = !(x > 5)
printf("%d", b );

[OUTPUT: 0]
-------------------------

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6 . Bitwise Operator :

Bitwise operators performs operations on bits.
AND ( & ),  OR ( | ),  XOR ( ^ ),  NOT ( ~ ).
Truth Table:

----------------------------------
A   B    A&B   A|B    A^B    ~A
----------------------------------
0   0    0      0     0       1
----------------------------------
0   1    0      1     1       1
----------------------------------
1   0    0      1     1       0
----------------------------------
1   1    1      1     0       0
----------------------------------

Example :

#include<stdio.h>
int main( )
  {
   int a = 6;
   int b = 3;
   int r1 = a & b;
   int r2 = a | b;
   int r3 = a ^ b;
   int r4 = ~a;
   printf("%d, %d, %d, %d",r1,r2,r3,r4);
   return 0;
  }

[ OUTPUT: 2, 7, 5, -7 ]

DESCRIPTION
    a = 0000 0110
    b = 0000 0011
 ---------------------
  a&b = 0000 0010 = 2
 ---------------------
  a|b = 0000 0111 = 7
 ---------------------
  a^b = 0000 0101 = 5
 ---------------------
  ~a  = 1111 1001 = -7
 ---------------------
In ~a the first bit(Most significant bit ) is 1 that represents number is negative, so for negative values system evaluates 2s compliment of the bit and print magnitude with minus (-) symbol. 
   So,
       ~6 = 1111 1001
 1s 0f ~6 = 0000 0110
                   +1
 ---------------------
 2s of ~6 = 0000 0111 = 7
----------------------
so, result is -7.

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7 . Conditional Operator ( ? : )

Conditional operator is also known as the ternary operator. It takes three operands and evaluates the boolean expression.

Example:

#include<stdio.h>
int main()
 {
  int a = 10, b = 20, max;
  max = ( a > b) ? a : b;
  printf("Max = %d",max);
  return 0;
 }

OUTPUT:

Max = 20

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Shift Operator (<<, >>) :

Shift operator are used to shift the bits of a number towards left or right.
1. Left Shift Operator      : <<
2. Right Shift Operator   : >>

Syntax :

   n ShiftOperator t

Here :
n : Perform shift on n's bits.
t : number of times.

Example:

1. Left Shift ( << ) 
#include<stdio.h>
int main()
 {
  int x = 6 << 2;
  printf("%d",x);
  return 0;
 }

  [ OUTPUT : 24]
-----------------------------------
2. Right Shift ( >> ) 
#include<stdio.h>
int main()
 {
  int x = 6 >> 2;
  printf("%d",x);
  return 0;
 }

  [ OUTPUT : 1]
-----------------------------------
DESCRIPTION :
  6 << 2 means :
  We need to perform left shift on bits of 6, 2 times

          6 = 0000 0110
first time  = 0000 1100
second time = 0001 1000 = 24

  6 >> 2 means :
  We need to perform right shift on bits of 6, 2 times

          6 = 0000 0110
first time  = 0000 0011
second time = 0001 0001 = 1

Next topic is escape-sequences

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