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COP3503c Lab 3- Pointers and Operator Overloading Solution
Laura Cruz Castro, Justin Lopez, Diego Aguilar, Cameron Brown
Contents
1 Intro and Problem 2
2 Background 2
2.1 Array Declaration and Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.2 Pointers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.3 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3 Specifications 3
3.1 Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.2 Methods in Contact class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.3 Required methods: ContactBook class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4 Testing and Help 5
5 Helpful links 5
1
2 BACKGROUND
1 Intro and Problem
In this lab we will be creating a database for contacts to be stored. Devices having overlapping contacts is inefficient as each device storing duplicate contacts wastes space. So, in this lab all Contact information will be stored in one place, and on each persons device will be a single ContactBook object, a class/struct that you will implement, along with a Contact class/struct you will implement. The ContactBook object will only hold pointers of contacts, to greatly reduce the total amount of memory used for a large database. So now when two devices have the same contact, they will both only hold a pointer to the same contact in memory, instead of there being two copies of the contact.
More specifically, a pointer in cpp on a 64 bit device is only taking up 8 bytes, where a contact might be holding way more bytes of information. In our example, there is only two strings for a contact to make it simpler(name and number), but it wouldn’t be difficult to add things like email, profile picture, and more to each contact, which would take up a lot more memory.
2 Background
2.1 Array Declaration and Initialization
You can initialize the array at the time of declaration or later using a loop or individual assignments.
In addition, to access specific elements of the array, you can use indexing. For example, to access the third element of the previous array, you can do the following:
2.2 Pointers
To declare a pointer, use the type followed by an asterisk (*). Pointers can be initialized with the address of a variable. You can use asterisk (*) to access the value stored at the address.
Pointers can be set to nullptr when not pointing to a valid address.
In C++, the arrow operator (->) is used to access members of a class or structure through a pointer.
It provides a convenient syntax for accessing members when working with pointers to objects. The arrow operator is an alternative to the dot operator (.) used with objects directly. Here’s a short example:
2.3 References 3 SPECIFICATIONS
2.3 References
In C++, references provide a way to work with variables directly, allowing you to pass values into functions and return values from functions.
Passing by Reference:
Pass variables by reference to avoid unnecessary copying and to allow modification of the original variable.
The function modifyValue takes an integer reference as a parameter, allowing it to modify the original variable num.
Returning Reference from a Function:
You can return a reference from a function, allowing the result to be modified directly
3 Specifications
3.1 Structure
• Both the name and phone number will be stored as string’s, as an example structure follows:
• You must use an array of Contact pointers in your ContactBook Class, an example structure follows:
3.2 Methods in Contact class 3 SPECIFICATIONS
• When using static arrays in cpp, the size that needs to be allocated must be known at COMPILE TIME, so we must set some kind of max size if we are using static arrays. This is why in most cases, std::vector will be more useful, as it resizes itself. We will learn in the next lab how we can resize dynamically allocated arrays, but know that a static array like this cannot be deleted and resized later.
• Note that the Contact and ContactBook class must be made independently of each other, since we will be adding contacts directly to the book by passing an actual Contact object to it. This means that the Contact class can NOT be made inside of the ContactBook class.
3.2 Methods in Contact class
• Parameterized Constructor passing two string parameters (Required)
• getName, which returns the name of the contact
• getNumber, which returns the number of the contact
• Display, which will not return anything, and just display the contact info. <Name>, <Number>
3.3 Required methods: ContactBook class
• Default Constructor, Copy Constructor, and Assignment operator
• Find - Takes in a string that can either be a phone number or a name and returns the found contact as a pointer. Returns a nullptr if a given string is not a name or a number in the contact system.
• Add - Takes in a contact object and stores its memory address in the furthest-most empty position in the array. The current order of contacts in the array must be preserved. (Note: passing by value will result in a garbage pointer). It returns nothing. Also know that there will never be a test case that tries to add a Contact that already exists in the ContactBook, and this applies for all the addition functions, even the operators.
• AddContacts - Takes in a vector of contact pointers, and stores all of it’s values in the class’s array, in the same order that they were in the vector. It returns nothing.
• Display - Displays each contact in the contact book, in the order that they are stored in the array:
Roland, 456-789-0123
Andres, 987-654-3210
George, 234-567-8901
• Alphabetize - sorts the array in alphabetical order based on contact name. Note that in this special case, Albert would come before Alberta. This should be the only function that can alter the order that the contacts are stored in the array. (see page 5 for info on std::sort)
• the following operators:
◦ += Contact - Adds a single contact to a ContactBook object.
◦ += ContactBook - Adds all contacts from the passed in ContactBook to this object. Adding them to the back in the order they are in the other ContactBook’s array.
◦ + ContactBook - Adds two contact books together and returns the resulting ContactBook.
◦ -= Contact - Removes the Contact that matches the passed-in Contact.
◦ -= ContactBook - Removes all contacts from a passed in ContactBook from this object.
◦ - ContactBook - Same as above, but returns a new ContactBook object as the result instead of modifying the current one.
◦ != ContactBook - Same as above, but the not equal operator.
5 HELPFUL LINKS
4 Testing and Help
5 Helpful links
• A good explanation of pointers
• Explanation of → and . dereferencing operators
!
While the implementation of any lab or project is entirely up to you (given that it meets our specifications), we recommend using std::sort for this lab! You can find the documentation here. Note that this can mean using functors or lambda which isn’t a topic we cover until later in the course. Knowing your way around the standard template library, especially std::sort, will be extremely helpful!
Contents
1 Intro and Problem 2
2 Background 2
2.1 Array Declaration and Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.2 Pointers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.3 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3 Specifications 3
3.1 Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.2 Methods in Contact class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.3 Required methods: ContactBook class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4 Testing and Help 5
5 Helpful links 5
1
2 BACKGROUND
1 Intro and Problem
In this lab we will be creating a database for contacts to be stored. Devices having overlapping contacts is inefficient as each device storing duplicate contacts wastes space. So, in this lab all Contact information will be stored in one place, and on each persons device will be a single ContactBook object, a class/struct that you will implement, along with a Contact class/struct you will implement. The ContactBook object will only hold pointers of contacts, to greatly reduce the total amount of memory used for a large database. So now when two devices have the same contact, they will both only hold a pointer to the same contact in memory, instead of there being two copies of the contact.
More specifically, a pointer in cpp on a 64 bit device is only taking up 8 bytes, where a contact might be holding way more bytes of information. In our example, there is only two strings for a contact to make it simpler(name and number), but it wouldn’t be difficult to add things like email, profile picture, and more to each contact, which would take up a lot more memory.
2 Background
2.1 Array Declaration and Initialization
You can initialize the array at the time of declaration or later using a loop or individual assignments.
In addition, to access specific elements of the array, you can use indexing. For example, to access the third element of the previous array, you can do the following:
2.2 Pointers
To declare a pointer, use the type followed by an asterisk (*). Pointers can be initialized with the address of a variable. You can use asterisk (*) to access the value stored at the address.
Pointers can be set to nullptr when not pointing to a valid address.
In C++, the arrow operator (->) is used to access members of a class or structure through a pointer.
It provides a convenient syntax for accessing members when working with pointers to objects. The arrow operator is an alternative to the dot operator (.) used with objects directly. Here’s a short example:
2.3 References 3 SPECIFICATIONS
2.3 References
In C++, references provide a way to work with variables directly, allowing you to pass values into functions and return values from functions.
Passing by Reference:
Pass variables by reference to avoid unnecessary copying and to allow modification of the original variable.
The function modifyValue takes an integer reference as a parameter, allowing it to modify the original variable num.
Returning Reference from a Function:
You can return a reference from a function, allowing the result to be modified directly
3 Specifications
3.1 Structure
• Both the name and phone number will be stored as string’s, as an example structure follows:
• You must use an array of Contact pointers in your ContactBook Class, an example structure follows:
3.2 Methods in Contact class 3 SPECIFICATIONS
• When using static arrays in cpp, the size that needs to be allocated must be known at COMPILE TIME, so we must set some kind of max size if we are using static arrays. This is why in most cases, std::vector will be more useful, as it resizes itself. We will learn in the next lab how we can resize dynamically allocated arrays, but know that a static array like this cannot be deleted and resized later.
• Note that the Contact and ContactBook class must be made independently of each other, since we will be adding contacts directly to the book by passing an actual Contact object to it. This means that the Contact class can NOT be made inside of the ContactBook class.
3.2 Methods in Contact class
• Parameterized Constructor passing two string parameters (Required)
• getName, which returns the name of the contact
• getNumber, which returns the number of the contact
• Display, which will not return anything, and just display the contact info. <Name>, <Number>
3.3 Required methods: ContactBook class
• Default Constructor, Copy Constructor, and Assignment operator
• Find - Takes in a string that can either be a phone number or a name and returns the found contact as a pointer. Returns a nullptr if a given string is not a name or a number in the contact system.
• Add - Takes in a contact object and stores its memory address in the furthest-most empty position in the array. The current order of contacts in the array must be preserved. (Note: passing by value will result in a garbage pointer). It returns nothing. Also know that there will never be a test case that tries to add a Contact that already exists in the ContactBook, and this applies for all the addition functions, even the operators.
• AddContacts - Takes in a vector of contact pointers, and stores all of it’s values in the class’s array, in the same order that they were in the vector. It returns nothing.
• Display - Displays each contact in the contact book, in the order that they are stored in the array:
Roland, 456-789-0123
Andres, 987-654-3210
George, 234-567-8901
• Alphabetize - sorts the array in alphabetical order based on contact name. Note that in this special case, Albert would come before Alberta. This should be the only function that can alter the order that the contacts are stored in the array. (see page 5 for info on std::sort)
• the following operators:
◦ += Contact - Adds a single contact to a ContactBook object.
◦ += ContactBook - Adds all contacts from the passed in ContactBook to this object. Adding them to the back in the order they are in the other ContactBook’s array.
◦ + ContactBook - Adds two contact books together and returns the resulting ContactBook.
◦ -= Contact - Removes the Contact that matches the passed-in Contact.
◦ -= ContactBook - Removes all contacts from a passed in ContactBook from this object.
◦ - ContactBook - Same as above, but returns a new ContactBook object as the result instead of modifying the current one.
◦ != ContactBook - Same as above, but the not equal operator.
5 HELPFUL LINKS
4 Testing and Help
5 Helpful links
• A good explanation of pointers
• Explanation of → and . dereferencing operators
!
While the implementation of any lab or project is entirely up to you (given that it meets our specifications), we recommend using std::sort for this lab! You can find the documentation here. Note that this can mean using functors or lambda which isn’t a topic we cover until later in the course. Knowing your way around the standard template library, especially std::sort, will be extremely helpful!
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