Description
Homework 5
1. Matrix: 40 Points
File: matrix.cpp
In this problem you will implement arbitrary sized matrix that can hold elements
of any type (defined by a template parameter T). You will create a class Matrix
which has two constructors Matrix() (creates empty matrix) and Matrix(int m,
int n) (creates m by n matrix). The destructor ~Matrix() needs to deallocate
the memory which holds matrix elements. Apply rule of three, so add copy
constructor and assignment operator. Additionally, you need to implement
following operators:
• operator* (multiplies two matrices and returns new matrix),
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• operator+ (adds two matrices and returns new matrix),
• operator[] (returns an element addressed with one index),
• operator() (returns an element addressed with two indices),
• operator<< (sends a matrix to ostream; do not use std::cout in the operator), and
• operator>> (reads a matrix).
The matrix element types tested in the main will only be double and int thus
you need two instances of the templated Matrix. As usual, the input will contain
the number of cases and for each case the operation to perform, the type of the
operands, and the two matrices. The size of each matrix is specified by two
numbers (m – number of rows and n – number of columns) and its elements.
After performing the specified operation you need to print the resulting matrix.
All inputs will be valid, so there is no need to check if the input are numbers or
that the matrix sizes are compatible.
Example Input
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multiply
int
2 3
1 2 3
5 6 7
3 5
-9 8 7 6 5
4 3 2 1 0
1 0 0 1 3
add
double
2 2
1 0
0 1
2 2
5 2
3 4
add
int
1 3
10 9 -98
1 3
10 0 99
2
Example Output
Case 0:
2 14 11 11 14
-14 58 47 43 46
Case 1:
6 2
3 5
Case 2:
20 9 1
2. Contact Manager: 60 Points
Files:
• contact.cpp, contact.h
• contacts_main.cpp
What makes associative containers like std::map powerful and useful is that
they can associate keys with values and quickly find the value associated with a
specific key. For example in a contact manager we want to be able to associate
a person’s name with some information about them (like phone number, e–mail,
etc.) and quickly look up this information given a first and last name. In
this problem you will create a contact management tool that will store some
information about the user’s contacts and allow them to list them, add or remove
contacts and search for a contact by name.
Contact Information
For each contact you will store the following data:
• First name
• Last name
• Phone number. Note: while phone numbers are “numbers” they are not
numeric (like an int), they are strings of characters in [0, 9]. Do not store
the phone number as an int.
• E–mail address
The contact information should be stored in a class (maybe called Contact)
declared in contact.h and defined in contact.cpp. Your contact class should
also provide a default constructor (one that takes no parameters) as this is
needed by the std::map to perform some operations.
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User Interaction
The user will need to be able to interact with the contact manager by
adding/removing contacts, searching by name and listing all contacts in the
manager. They should also be able to exit the manager. To indicate to the user
that the program is awaiting their input you should print a caret (>) followed by
a space as a prompt. In the examples below the user input and expected output
are shown interleaved, with the user input preceeded by the prompt.
After receiving and executing the user’s command you should return to the
initial input prompt so they can enter another command. Examples of a full
interactive session are shown after the details of each command. To help you
start this is what your main function should look like to loop over and handle a
user’s commands until they enter “exit”. You can use this as starter code for
your program. Note that there is no cases loop in this assignment, just the user
interaction loop.
int main(){
std::string cmd;
do {
if (cmd == “exit”){
break;
} else if (cmd == “list”){
// List contacts in the manager
} else if (cmd == “add”){
// Add a contact to the manager
} else if (cmd == “remove”){
// Remove a contact from the manager
} else if (cmd == “find”){
// Find a contact in the manager
}
// Print a terminal prompt so the user knows
// we’re waiting for their input
std::cout << "> “;
} while (std::cin >> cmd);
return 0;
}
Listing All Contacts
When the user enters the list command and you should print out the first and
last names of all the contacts in the manager. If there are no contacts in the
manager you should just print no contacts. The contacts should be printed in
alphabetical order, sorted by last name then by first name. This sorting will be
done automatically for you if you build the key in the std::map properly.
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Example: The manager contains three people: Grace Hopper, Dennis Ritchie
and Leslie Lamport
> list
Hopper, Grace
Lamport, Leslie
Ritchie, Dennis
Example: The manager is empty.
> list
no contacts
Adding a Contact
When the user enters the add command you should prompt them to enter the first
name, last name, phone number and e–mail address for the contact, one after the
other. You should print a prompt each time so the user knows what the program
is expecting them to input. First you should read the first name and print
the prompt first name:, for the last name the prompt is last name:, for the
phone number it’s phone number: and for the e–mail address it’s e-mail:. If a
contact with same first and last name is already in contact manager,
then overwrite it with this new contact.
Note that there is a trailing space after the colon printed for each prompt so
the user’s input doesn’t run right against the prompt.
Example: The user wants to add Ada Lovelace as a contact.
> add
first name: Ada
last name: Lovelace
phone number: 555123456
e-mail: ada@lovelace.mathmail
Removing a Contact
When the user enters the remove command you should prompt them to enter the
first and last name of the contact, with the same prompts used when adding a
contact (first name: and last name:). If the contact is found they should be
removed from the list and you should print a confirmation of the form removed
FIRST LAST where FIRST and LAST are the first and last name of the contact
that was removed. If no contact is found with the name entered you should print
out contact not found.
Example: The user wants to remove Richard Stallman, who is in the manager.
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> remove
first name: Richard
last name: Stallman
removed Richard Stallman
Example: The user wants to remove John McCarthy, who is not in the manager.
> remove
first name: John
last name: McCarthy
contact not found
Finding a Contact
When the user enters the find command you should prompt them to enter the
first and last name to search for, using the same prompt style as before. If the
contact is found you should print out the full information about the contact
(the name, phone number and e–mail address). If the contact is not found you
should print out contact not found.
If a contact is found the contact’s information should be printed out as:
Name: FIRST LAST
Phone Number: PHONENUMBER
E-mail: EMAIL
Where FIRST, LAST, PHONENUMBER and EMAIL correspond to the contact’s
data.
Example: The user searches for Donald Knuth, who is in the manager.
> find
first name: Donald
last name: Knuth
Name: Donald Knuth
Phone Number: 555898123
E-mail: knuth@donald.texmail
Example: The user searches for Edsger Dijkstra, who is not in the manager.
> find
first name: Edsger
last name: Dijkstra
contact not found
Exiting the Manager
When the user enters the exit command your program should exit as done in
the main function provided for you above. There is no example use case as the
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only thing your program should do after receiving the “exit” command is exit.
Some Notes and Hints on std::map
You should use a std::map to store the contact information where the keys will
be some combination of their first and last name (as people can have the same
first or last name, but not both) and the value will be your Contact struct. The
actual values returned by the iterator over your map will be a std::pair
To access each element of the pair you can use first or second as shown below.
std::map
for (const auto &e : my_map){
// first accesses the key, second accesses the value
std::cout << e.first << " mapped to " << e.second << "\n";
}
This code will print:
bob mapped to 2
hello mapped to 4
To insert into a map we can index it by the key with operator[]. If the key is
not found a new entry is created using the default constructor and a reference
returned (this is why we need a default constructor for Contact), if the key is
found the existing entry will be returned.
std::map
// Create key, value pair for joe and set it to 10
std::string joe = “joe”;
my_map[joe] = 10;
// Update the existing entry for hello
my_map[“hello”] = 5;
for (const auto &e : my_map){
// first accesses the key, second accesses the value
std::cout << e.first << " mapped to " << e.second << "\n";
}
This code will print:
bob mapped to 2
hello mapped to 5
joe mapped to 10
To find an entry by its key you can use find, see the interactive example on the
documentation page for usage, and for how to see if the key was not found. Since
the map will create the entry if it’s not found when indexing with operator[]
you must use find to see if a key exists in the map. find returns an iterator so
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we can use find and erase to remove an element by its key since erase takes
the iterator to the element that we want to remove.
You can assume that you will receive valid input and commands and for simplicity
that case does matter, for example Dennis Ritchie is a different person than
dennis ritchie.
Example Usage
Interactive Session
Since the program is interactive just reading the output can be kind of confusing.
Instead you can copy-paste the sample input (from contacts_stdin.txt) to
the console to see what the actual usage would look like. You should see the
following if you paste the sample input into your console. There is no case loop
for this problem, just the user interaction loop.
> list
no contacts
> add
first name: Ada
last name: Lovelace
phone number: 555123456
e-mail: ada@lovelace.mathmail
> list
Lovelace, Ada
> add
first name: Grace
last name: Hopper
phone number: 555823457
e-mail: hopper@debugging
> add
first name: Dennis
last name: Ritchie
phone number: 555898123
e-mail: dennis@email
> add
first name: Leslie
last name: Lamport
phone number: 000912931
e-mail: leslie.lamport
> list
Hopper, Grace
Lamport, Leslie
Lovelace, Ada
Ritchie, Dennis
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> remove
first name: Dennis
last name: Ritchie
removed Dennis Ritchie
> remove
first name: Dennis
last name: Ritchie
contact not found
> list
Hopper, Grace
Lamport, Leslie
Lovelace, Ada
> find
first name: Dennis
last name: Ritchie
contact not found
> find
first name: Leslie
last name: Lamport
Name: Leslie Lamport
Phone Number: 000912931
E-mail: leslie.lamport
> add
first name: Dennis
last name: Ritchie
phone number: 555898123
e-mail: dennis@email2
> list
Hopper, Grace
Lamport, Leslie
Lovelace, Ada
Ritchie, Dennis
> find
first name: Dennis
last name: Ritchie
Name: Dennis Ritchie
Phone Number: 555898123
E-mail: dennis@email2
> add
first name: Dennis
last name: Ritchie
phone number: 555898123
e-mail: dennis@email
> add
first name: Bob
last name: Ritchie
9
phone number: 555898123
e-mail: dennis@email
> add
first name: Bob
last name: Jackson
phone number: 555898123
e-mail: dennis@email
> add
first name: Jack
last name: Jackson
phone number: 555898123
e-mail: dennis@email
> add
first name: Jack
last name: Jackson
phone number: 555898123
e-mail: dennis@email
> add
first name: Grace
last name: Hopper
phone number: 5551020001238123
e-mail: grace@email
> add
first name: Brian
last name: Kernighan
phone number: 555
e-mail: brian.kernighan@email
> list
Hopper, Grace
Jackson, Bob
Jackson, Jack
Kernighan, Brian
Lamport, Leslie
Lovelace, Ada
Ritchie, Bob
Ritchie, Dennis
> exit
Input/Output Redirected Session
See the stdin_stdout.zip file for the input/output files for this example since
it’s a bit hard to read the output here due to long lines.
Input:
list
10
add
Ada
Lovelace
555123456
ada@lovelace.mathmail
list
add
Grace
Hopper
555823457
hopper@debugging
add
Dennis
Ritchie
555898123
dennis@email
add
Leslie
Lamport
000912931
leslie.lamport
list
remove
Dennis
Ritchie
remove
Dennis
Ritchie
list
find
Dennis
Ritchie
find
Leslie
Lamport
add
Dennis
Ritchie
555898123
dennis@email2
list
find
Dennis
Ritchie
add
Dennis
11
Ritchie
555898123
dennis@email
add
Bob
Ritchie
555898123
dennis@email
add
Bob
Jackson
555898123
dennis@email
add
Jack
Jackson
555898123
dennis@email
add
Jack
Jackson
555898123
dennis@email
add
Grace
Hopper
5551020001238123
grace@email
add
Brian
Kernighan
555
brian.kernighan@email
list
exit
Expected Output
> no contacts
> first name: last name: phone number: e-mail: > Lovelace, Ada
> first name: last name: phone number: e-mail: > first name: last name: phone number: e-mail: > first name: last name: phone number: e-mail: > Hopper, Grace
Lamport, Leslie
Lovelace, Ada
Ritchie, Dennis
> first name: last name: removed Dennis Ritchie
> first name: last name: contact not found
> Hopper, Grace
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Lamport, Leslie
Lovelace, Ada
> first name: last name: contact not found
> first name: last name: Name: Leslie Lamport
Phone Number: 000912931
E-mail: leslie.lamport
> first name: last name: phone number: e-mail: > Hopper, Grace
Lamport, Leslie
Lovelace, Ada
Ritchie, Dennis
> first name: last name: Name: Dennis Ritchie
Phone Number: 555898123
E-mail: dennis@email2
> first name: last name: phone number: e-mail: > first name: last name: phone number: e-mail: > first name: last name: phone number: e-mail: > first name: last name: phone number: e-mail: > first name: last name: phone number: e-mail: > first name: last name: phone number: e-mail: > first name: last name: phone number: e-mail: > Hopper, Grace
Jackson, Bob
Jackson, Jack
Kernighan, Brian
Lamport, Leslie
Lovelace, Ada
Ritchie, Bob
Ritchie, Dennis
>
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