Description
Smart Pointer Implementation
Quoting Wikipedia: In computer science, a smart pointer is an abstract data type that simulates
a pointer while providing added features, such as automatic memory management or bounds
checking. Such features are intended to reduce bugs caused by the misuse of pointers, while
retaining efficiency. Smart pointers typically keep track of the memory they point to, and may
also be used to manage other resources, such as network connections and file handles. Smart
pointers originated in the programming language C++.
In this last assignment, we will try to tackle the implementation of a “smart pointer” in its
simplest form.
Please note that for all the questions, you are responsible of providing the
appropriate test code in your main function. The output of your program should
reflect clearly the answers for each question. Failing to do so will be penalized.
Also note that you need to double check and confirm that your code compiles before
submitting to myCourses. The best way to minimize compilation issues on our side, is
to provide only one cpp file containing all the code.
Question 1 (15 pts)
Research smart pointers provided by the standard library (since C++11). List them and
explain the difference between them.
Question 2 (15 pts)
Design and implement your own smart pointer class called SmartPointer that will
automatically delete the memory for built-in integer type that is allocated through it.
SmartPointer class should be used this way in your main() function:
SmartPointer sPointer(11);
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Here we are passing 11 as an argument to the constructor of SmartPointer class. The
constructor will allocate an integer variable and will initialize it to 11.
To get the value of your variable, you should provide and implement a method called
getValue(). You use it this way:
cout << sPointer.getValue(); // prints 11
You should also be able to differ the initialization of your allocated int variable to a later
moment. For example the following code should be supported as well:
SmartPointer sPointer;
sPointer.setValue(133);
cout << sPointer.getValue(); // prints 133
Please note that for this question, SmartPointer class will only handle allocation of integer
type variables. Allocating arrays is not supported to keep the class simple. No reference
counting is required.
The default constructor should allocate and initialize the allocated integer to zero. The
destructor should take care of deleting the allocated memory.
Question 3 (15 pts)
Exceptions are problems encountered during the execution of the program. For example, if
the system runs out of memory during a dynamic allocation, it will raise an exception.
These exceptions should be treated whenever they are raised in order to avoid the
program from yielding undefined behavior or even worst, crashing.
Add appropriate exception handling for the SmartPointer class to treat the following 2
cases:
1. When allocating a new variable, the code should throw an exception if the system
runs out of memory. This exception should be treated and a message should be
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displayed to the screen warning the user that the variable was not being allocated. I
am aware that this cannot really be tested out of the box, so I’m not expecting your
main to provide a test case for this situation. However, I want to see that your code
“catch” the appropriate exception that the operating system throws when it runs out
of memory.
2. Let’s assume that we are only interested in positive numbers. The code should
throw an exception whenever a user tries to assign a negative number to any
variable that was being allocated through SmartPointer class. This exception should
be treated and a message should be displayed to the screen warning the user that
the class does not handle negative numbers.
Question 4 (15 pts)
Make the class SmartPointer generic using templates to be able to allocate any built-in type
through it (int, float, double). Let’s ignore char and string types for simplicity.
Use case:
SmartPointer
sPointer.setValue(13.31);
cout << sPointer.getValue();
Question 5 (20 pts)
Overload the operators +, - and * to be able to perform arithmetic operations on variables
allocated through SmartPointer class. Don’t use member methods for the overloaded
functions, use friend functions instead. These overloaded functions should be generic as
well (using templates).
Use case:
SmartPointer
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sPointer1.setValue(1.5);
SmartPointer
sPointer2.setValue(2.5);
SmartPointer
cout << sPointer3.getValue() << endl; // prints 4
Question 6 (20 pts)
How can you adapt the class SmartPointer to be able to handle allocation of arrays? Please
provide a full implementation. Feel free to choose any suitable signature for your class,
including the way it should be used.
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