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CS100 Homework 7 (Spring, 2022)
Deadline: 2022-05-30 23:59:59
Late submission will open for 24 hours after the deadline, with -50% point deduction.
Problem 1. Gradesheet
In this problem, you are going to implement a simple Gradesheet class. The students’ grades are recorded
in a grade sheet. Each student has their name, student number and grade, which are covered in the Grade
class (See the code for details). You need to implement the all the getters and setters of Grade.
All grades are stored in a std::vector inside a Gradesheet class. You need to implement all the
provided member functions as follows.
• Default constructor and destructor. The default constructor initializes an empty grade sheet.
• Return the size of gradesheet, that is the number of records in this gradesheet.
std::size_t size() const;
• Compute the average of all students’ grades.
double average() const;
• Add a new student’s grade into the gradesheet. If the student’s name or student number already
exists, do nothing and return false. Otherwise, add the grade and return true.
bool addGrade(const Grade &grade);
• Return the grade of the student with the given name or student number. Return -1 if such student
is not found.
double findByName(const std::string &name);
double findByNumber(int number);
• Overloading subscript operator. Returns a reference to the i-th Grade recorded in the grade sheet.
The numbering starts with 0.
Grade& operator[](size_t i);
const Grade& operator[](size_t i) const;
CS100 Homework 7 (Spring, 2022) Deadline: 2022-05-30 23:59:59
• Overloading operator<< which applied to an output stream. The desired output should be like:
There are 3 columns in total. Each column is 10 characters wide. There are 30 ’-’ for those dashed
lines. Each row contains the student name, number and grade. Notice that all the numbers and
strings should be left-aligned. For the grades, you should print the number with a precision of 3
(use std::precision(3)). DO NOT forget to add the boundary as shown in the example above.
friend std::ostream& operator<<(std::ostream& os, const Gradesheet& sheet);
• Sort the gradesheet by student name in alphabetical order or by student number in ascending
order or by grade in descending order. You can use std::sort from for simplicity.
We also provide you 3 classes (NameComparator, NumberComparator, GradeComparator). You
should overload the operator() of each class for comparison.
void sortByName();
void sortByNumber();
void sortByGrade();
Sample code
Gradesheet sheet;
sheet.addGrade(Grade("Bob", 1, 95));
sheet.addGrade(Grade("Carl", 2, 100));
sheet.addGrade(Grade("Alex", 3, 90));
std::cout << "size == " << sheet.size() << "\n" << sheet;
The output is
size == 3
|Name Number Grade |
|Carl 2 100 |
|Bob 1 95 |
|Alex 3 90 |
• The Grade class is very simple with only one constructor, some getters and some setters. The
constructor initializes every member with the corresponding parameter. Complete this class first.
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CS100 Homework 7 (Spring, 2022) Deadline: 2022-05-30 23:59:59
• You may find std::setw, std::setprecision and std::left defined in standard library file
helpful to implement the operator<<.
• It is guaranteed that the length of the student name and number will not exceed 10.
Submission Guideline
When you submit your code, your main function will be replaced by one on OJ. You MUST NOT modify
the definition of the class. Otherwise, you will NOT receive any scores.
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CS100 Homework 7 (Spring, 2022) Deadline: 2022-05-30 23:59:59
Problem 2. Singly Linked-List
In this task, you will need to write an STL-style templated singly-linked-list and its iterator. Considering
that many of you may have only a vague idea of template programming, we have provided a framework
for you so that you don’t have to learn too many things. Moreover, since the compiler won’t generate
any code for templated functions that are not used, we also provide a simple test which involves some
compile-time checks and some runtime tests. You can paste or #include your code at the beginning of
7-2 simple tests.cpp to run the simple test.
In the framework, first we have the Slist node class. This is a simple structure that defines the
node of the linked-list. You probably need to add some constructors for this class.
The Iterator
Then it comes the Slist iterator class, which defines the iterator of the linked-list. T is
the type of values that can be obtained by dereferencing the iterator. is const is a bool value denoting
whether this iterator is a const iterator. A const iterator differs from a regular iterator in that the
value that is being pointed to cannot be modified through a const iterator. In this sense, dereferencing
a const iterator should return a reference-to-const, and on a const Slist the begin() and end()
functions should return const iterators.
Every STL-style iterator should have the following type aliases: value type, difference type,
pointer, reference and iterator category. We have defined them for you and have provided explanation
in the framework. The m cur member points to the node containing the element that the
iterator is pointing to.
The iterator should meet the requirements of a ‘forward-iterator’: It must support operator* (dereference
operator), operator-> (arrow member-access operator) and operator++ (both prefix and postfix).
The operator-> might be a little bit tricky, so you only need to implement the other three operators.
We have provided the declarations of these functions and please DO NOT modify them, or you may
encounter compile-error.
Your operators must behave in consistency with the built-in behaviors. For example, ++iter returns
reference to the object ‘iter’, while iter++ returns a copy of the object before incrementation.
The Slist
Now let’s begin implementing the core part of this task. As in Slist iterator, there are some type
alias members that every STL container must have, and we have provided them for you. The Slist
has two data members. m head points to the head of linked list, and m length is the number of elements
stored in the list.
First, the Slist needs a default-constructor, a copy-constructor, a copy-assignment operator and a
destructor. You need to define them on your own. The requirements of these functions are stated in
the framework. In particular, we highly recommend using the ‘copy-and-swap’ technique to
implement the copy-assignment operator, which saves you a lot of work. If you don’t know what it is,
you can refer to the reference solution of hw5-1.
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CS100 Homework 7 (Spring, 2022) Deadline: 2022-05-30 23:59:59
Then you need to implement some operations on the linked-list. These operations are push front,
pop front, insert after and erase after. The requirements are stated in the framework. We have
provided the declarations for you and please DO NOT modify them, or you may encounter compileerror.
Note that we have defined the base() and next() functions in the Slist iterator class, which
you may find helpful.
The Slist should also support size(), empty() and clear(), which behave the same as in every
STL container. size() should return a value of the type ‘size type’, denoting the number of elements
stored in the list. empty() returns true if and only if the list contains no elements. clear() removes all
the elements in the list.
The well-known ‘begin()’ and ‘end()’ functions have been implemented for you.
In the end, you will also need to implement the operator== and operator< of Slist. Two Slists are
thought of as equal if and only if they are of the same length, and every pair of corresponding elements
are equal. The operator< compares two Slists in the lexicographical order. We strongly suggest
using std::equal and std::lexicographical compare defined in , which will save you a
lot of work.
Please do not declare unnecessary friends.
Special Requirements
When it comes to generic programming, it is best practice to minimize the number of requirements placed
on the unknown types.
• The template argument T, which denotes the type of the elements stored in the linked-list, may
not be default-constructible or copy-assignable. Considering that you have not learned
about variadic templates, perfect forwarding and move semantics, it is guaranteed that T is copyconstructible.
We have provided a Special type in the simple tests which is neither defaultconstructible
nor copy-assignable. Make sure that your Slist works well when T = Special type.
• It is guaranteed that operator== will be called only when
bool operator==(const T &, const T &)
is defined. operator< will be called only when
bool operator<(const T &, const T &)
is defined. Note that your operator< should not depend on other relational operators of T, like
operator> or operator!=. The Special type provided in the simple tests is an example, on which
only operator== and operator< are defined.
• Do not modify any code we have written for you, or you may encounter compile-error.
• Remove the comments when they are not needed, in order to improve readability of your code.
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CS100 Homework 7 (Spring, 2022) Deadline: 2022-05-30 23:59:59
Submission Guideline
Submit your code to the OJ. It should contain the Slist node, Slist iterator and Slist, as well as
some non-member operators. Do not contain any tests in your submission.
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