Programming Language C Tutorial – IV (Unary Operators, Logical Operators, Ternary Operators)

Unary Operators (++, --)

 It is also known as increment or decrement operators.

For ease understanding we have to classify it in following two types

1. Pre – Increment : First increment in value and then proceed further e.g. ++a, ++x etc. we evaluate it by simple example

Let us assume we declare int x=10; and then assign this value to another variable int y=++x; then we will find that value of x and y is now 11.

2. Post – Increment: First assign value and then get incremented. e.g. a++, x++ etc. we evaluate it by simple example

Let us assume we declare int x=10; and then assign this value to another variable int y=x++; then we will find that value of x is 11 and value of y is 10.

            Same things apply to decrement operator.

Logical Operator(&&, ||, !)

&&(and operator) – It evaluate the given conditions and retain true result if all conditions are satisfied otherwise false result.

Truth Table:

           

Condition1	Condition2	Condition..n	Result
True	True	True	True
True	True	False	False
True	False	True	False
False	True	True	False
False	False	False	False

For example:

            int a=10,b=20,c=5;

            int ans= a>10&&b<20&&c>5;

Here we will get false i.e. zero result (ans=0)

            int a=10,b=20,c=5;

            int ans= a>2&&b<50&&c>1;

Here we will get true i.e.1 result (ans=1)

You will try it by assuming different set of values and check all possible result.

||(or operator) – It evaluate the given conditions and return true result if only one condition is satisfied out of all conditions.

Truth Table:

           

Condition1	Condition2	Condition..n	Result
False	False	False	False
False	False	True	True
False	True	False	True
True	False	False	True
True	True	True	True

For example:

            int a=10,b=20,c=5;

            int ans= a>=10||b<20||c>5;

Here we will get true i.e. 1 result (ans=1)

            int a=10,b=20,c=5;

            int ans= a<2||b<5||c>10;

Here we will get false i.e.zero result (ans=0)

You will try it by assuming different set of values and check all possible result.

! (not operator) : It returns true if condition is false and returns false when condition is true.

Condition	Result
True	False
False	True

Conditional (Ternary) Operator

C offers a shorthand notation, which provides conditional execution of statements.

       The conditional operator has 2 parts? and :

Let us take a example- max=num1>num2?num1:num2;

The purpose of the above statement is to assign the value of  num1 or num2, whichever is larger, to the variable max.

First the condition (num1>num2) is evaluated. If it is true, the value num1 is assigned to max, else num2 is assigned to max.