Question

Here is a definition of a class called Pairs. Objects of type Pairs can be used in any situation where ordered pairs are needed. Your task is to write implementations of the overloaded operator >> and the overloaded opera- tor << so that objects of class Pairs are to be input and output in the form (5,6) (5,-4) (-5,4) or (-5,-6). You need not implement any constructor or other member, and you need not do any input format checking. #include using namespace std; class Pairs { public: Pairs( ); Pairs(int first, int second); //other members and friends friend istream& operator>> (istream& ins, Pairs& second); friend ostream& operator<< (ostream& outs, const Pairs& second); private: int f; int s; };

Short answer

Question: Write a short answer explaining how to implement the overloaded << and >> operators for a class, Pairs, that represents ordered pairs of integers without implementing any constructor or other member. Answer: To implement the overloaded << and >> operators for a class called Pairs, you need to create two friend functions: one for the input operation (>>) and one for the output operation (<<). In the input operation function, extract the integer elements from the input stream, skipping the characters such as parentheses and comma. In the output operation function, simply output the elements of the ordered pair in the specified format with parentheses and a comma separating the elements. This will enable input and output operations on ordered pairs of integers in the desired format for the Pairs class.

Step-by-step solution

Understand the Pairs class

From the given code, the Pairs class has two private data members, 'f' and 's', which represent the first and second element of the ordered pair. There are two public constructors and two friend functions that we will be implementing, the overloaded (>>) operator and the overloaded (<<) operator.

Implement the overloaded operator (>>)

To implement the overloaded (>>) operator, we need to extract the first and second elements of the input stream. We can do this by using the extraction operator (>>) on the input stream (ins) and extracting the integers, after skipping the necessary characters (parentheses and comma). ```cpp istream& operator>>(istream& ins, Pairs& second) { char ch; ins >> ch; // Skip the opening parenthesis '(' ins >> second.f >> ch; // Read the first integer, then skip the comma ins >> second.s >> ch; // Read the second integer, then skip the closing parenthesis ')' return ins; } ```

Implement the overloaded operator (

To implement the overloaded (<<) operator, we simply need to output the elements of the ordered pair in the specified format, with parentheses and a comma separating the elements. ```cpp ostream& operator<<(ostream& outs, const Pairs& second) { outs << '(' << second.f << ',' << second.s << ')'; return outs; } ``` With these implementations, the class Pairs now supports input and output operations on ordered pairs of integers in the desired format.

Key concepts

Operator Overloading

Operator overloading in C++ allows you to redefine how operators work with objects of your custom classes. It is especially useful when you want custom objects like the Pairs class to behave like basic data types under standard operations. In our case, the operators `>>` and `<<` are overloaded to handle input and output for the Pairs object.
- The `>>` operator is overloaded to read from an input stream. This allows users to input pairs like `(5,6)` directly into a Pairs object. - The `<<` operator is overloaded to write to an output stream. It makes it easy to output a Pairs object in the form `(5,6)`, for example.
The goal is to provide natural syntax for handling pairs, much like native C++ types, making the class more intuitive and flexible.

Input/Output Streams

Input and output streams in C++ are classes that allow you to read data from input devices and write data to output devices, such as the console or files. The iostream library facilitates the use of streams and includes the basic input (cin) and output (cout) streams.
In our class Pairs, the `istream` and `ostream` are crucial: - `istream` is used with the overloaded `>>` operator. It reads input from the user or a file and assigns the values to the object's attributes. - `ostream` is used with the overloaded `<<` operator. It outputs the object's data in a formatted manner to the console or another output device.
These streams handle text-based data easily, converting user-input strings into data types needed by applications, making them integral to modern C++ programming.

Friend Functions

Friend functions in C++ are functions that are not members of a class but have access to its private and protected members. They are useful when you want some external function to operate on the private data of a class.
In the Pairs class example, friend functions are used to define the input and output operators: - The `>>` operator function can access private members directly to fill in data without needing getters or public methods. - The `<<` operator function similarly accesses private members for display purposes.
The need for these functions arises from the requirement to extend the functionality of the class without exposing its internal data to the whole world, keeping the class encapsulated but practical.

Ordered Pairs

Ordered pairs are a fundamental concept in mathematics, representing a pair of elements with an ordered relationship. The first element of the pair is considered as the first position, and the second one is considered as the second position.
In the context of programming, an ordered pair is a data structure that stores two related objects. The Pairs class is designed to handle such data, where each object instance holds a pair of integers.
- The storage of data in pairs makes it easy to represent coordinates, key-value pairs, or other related data items. - Handling ordered pairs allows for operations where the relation between the two items is meaningful, like addition or mapping functions. The Pairs class, therefore, provides a structured way of dealing with two-component data, ensuring their inherent order is preserved during operations.