Page 161 - DCAP404 _Object Oriented Programming

Object-oriented Programming

Notes  Two approaches are used in such conversion: A one argument constructor changes a basic
type to a user defined type, and a conversion operator converts a user-defined type to a
basic type.
 When one user-defined type is converted to another, either approach can be used.

7.7 Keywords

Operator Overloading: Attaching additional meaning and semantics to an operator. It enables
to exhibit more than one operations polymorphically.
Strings: The C++ strings library provides the definitions of the basic_string class, which is a class
template specifically designed to manipulate strings of characters of any character type.

Unary Operators: Unary operators operate on one operand (variable or constant). There are two
types of unary operators- increment and decrement.

7.8 Review Questions

1. Overload the addition operator (+) to assign binary addition. The following operation
should be supported by +.

110010 + 011101 = 1001111
2. What will be the output of the following program snippet? Explain.

int x;
float y = 11.1883;
x=y;
cout<<x;

cout<<y;
3. Which operators are not allowed to be overloaded?

4. What are the differences between overloading a unary operator and that of a binary
operator? Illustrate with suitable examples.
5. Why is it necessary to convert one data type to another? Illustrate with suitable examples.

6. How many arguments are required in the definition of an overloaded unary operator?
7. When used in prefix form, what does the overloaded + + operator do differently from
what it does in postfix form?
8. Write the complete definition of an overloaded + + operator that works with the string
class from the STRPLUS example and has the effect of changing its operand to uppercase.
You can use the library function toupper ( ), which takes as its only argument the character
to be changed, and returns the changed character.
9. Write a note on unary operators.

10. What are the various rules for overloading operators?

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