[Solved] EXPERIMENT NO 5 Operator Overloading

Operator Overloading

Objectives

In this lab students will learn to overload,

• Arithmetic operators
• Relational operators
• Logical operators Unary operators

Equipment required

• Visual Studio/ Dev C++/Eclipse installed in Windows/PC

Operator Overloading

In C++ the overloading principle applies not only to functions, but to operators too. That is, of operators can be extended to work not just with built-in types but also classes. A programmer can provide his or her own operator to a class by overloading the built-in operator to perform some specific computation when the operator is used on objects of that class. The following set of operators is commonly overloaded for user-defined classes:

• = (assignment operator)
• +, -, *, , (binary arithmetic operators)
• +=, -=, *=, (compound assignment operators)
• ==, !=, >, <, >=, <=, (comparison operators)

Operator overloading is a clear representation of operations performed, and is used because it allows the developer to program using notation closer to the target domain and allows userdefined types a similar level of syntactic support as types built into the language, for example, consider variables a, b, c of some user-defined type, such as matrices:

a + b * c

In a language that supports operator overloading, and with the usual assumption that the * operator has higher precedence than + operator, this is a concise way of writing:

add (a, multiply (b,c))

You cannot create new operators like *& and try to overload them; only existing operators can be overloaded. The precedence of an operator cannot be changed by overloading. The associativity (i.e., left-to-right, or right-to-left) of an operator cannot be changed. The arity (i.e., no. of operands) of an operator cannot be changed. The meaning of how an operator works on built-in types cannot be changed. Operator overloading works only on objects of user defined types or with a mixture of user-defined and built-in types.

BEMTS-F20- A Air University, Islamabad

Example

LAB TASKS

Q1. Create a class RationalNumber that stores a fraction in its original form (i.e., without finding the equivalent floating pointing result). This class models a fraction by using two data members: an integer for numerator and an integer for denominator. For this class, provide the following functions:

• A no-argument constructor that initializes the numerator and denominator of a fraction to some fixed values.
• A two-argument constructor that initializes the numerator and denominator to the values sent from calling function. This constructor should prevent a 0 denominator in a fraction, reduce or simplify fractions that are not in reduced form, and avoid negative denominators.
• A display function to display a fraction in the format a/b.
• An overloaded pre and post increment operator to increment the data members.
• An overloaded operator for subtraction of two rational numbers. Two fractions a/b and c/d are subtracted from each other as:

• An overloaded operator / for division of two rational numbers. If fraction a/b is divided by the fraction c/d, the result is

• An overloaded relational operator >= should return a variable of type bool to indicate whether 1st fraction is greater than or equal to 2nd or not
• Overloaded equality operator == should return a variable of type bool to indicate whether 1st fraction is equal to the 2nd fraction or not.