Unary Operators Friend Function Type Conversion

1. Operator Overloading and
Type Conversion
Chapter – 10

2. 10.1 Introduction
 Operator Overloading is similar to that of Function Overloading.
 It is a type of Polymorphism
 Polymorphism allows to permit multiple definitions for functions and
operators
 Operator Overloading helps the programmer to use the operators with
objects of classes.
 Eg. Book

3. 10.2 The Keyword Operator

4. 10.3 Overloading Unary Operators
 Overloading of explicit argument to an operator function is
called unary operator overloading.
 Operators ++ , -- and – are unary operator.
 Unary operator ++ and – can be used as prefix or suffix with
functions
 Eg. Book

5. 10.7 Overloading with friend Function
 friend functions are more useful in operator overloading.
 Difference b/n member function and friend function is the member function takes
argument explicitly.
 friend function needs parameters to be explicitly passed
 Syntax:

6. 10.9 Type Conversion
Three possibilities of Data Conversions are
Conversion from Basic Data type to User-defined data type(class
type)
Conversion from class type to basic data type
Conversion from one class type to another class type

7. 10.9.1Conversion from Basic to class type
It is automatically done by the compiler with the help of
built-in routines or by applying type casting.
Here , left-hand operand of = sign is always class type and
right-hand sign operand is always basic type
Eg. Book

8. 10.9.2 Conversion from Class type to Basic Data Type
 Compiler does not know about user defined data type built using
classes.
 Programmer needs explicitly tell the compiler about the conversion
from class to basic type
 Such type of conversion is known as Overloading of type cast
operators
 Here left-hand operand is always basic data type
 Right-hand operand is always of class type

9. 10.9.2 Conversion from Class type to Basic Data Type
 During conversion , statement should satisfy following conditions
:
 The conversion function should not have any argument
 Do not mention return type
 It should be a class member function
 Eg. Book

10. 10.9.3 Conversion from One Class type to Another
Class Type
When an object of one class is assigned to object
of another class, important to give clear
instructions to compiler about how to make
conversion b/n 2 user-defined data type.

11. 10.10 Rules for Overloading Operators
When an operator is overloaded ,its properties
like syntax , precedence and associatively
remain constant