Assignment {8.1 A} [20 points]

Rewrite your high scores program that uses a highscore struct -- but use an STL vector instead of an array. (Note, you will be using an STL vector, not the MyVector class developed in lesson 19.) You may use your own solution from the earlier assignment or the posted solution from that assignment.

Clarifications and Additional Requirements:

Documentation is not required for this assignment.

All requirements of the earlier assignment apply. Your program should use three functions that accept the vector of highscore structs (the size parameter from the earlier assignment won't be needed now, since a vector knows its own size). You must use these function headers:

void initializeData(vector& scores) void sortData(vector& scores) void displayData(const vector& scores) 

The name field in the struct must still be a c-string

The focus of this assignment is to use iterators. I expect you to use iterators wherever possible to access the vector. As a result, you must not use square brackets, the push_back() function, the at() function, etc. You won't get full credit if you miss an opportunity to use iterators.

You should still ask the user to enter the number of scores there will be, and then you should create a vector with the required capacity. You can do this by using the vector class's constructor that creates a vector with the capacity indicated by its parameter. For example, to create a vector of size 100, use this:

vector myExampleVector(100);

It is possible to write our program without bothering to indicate a size if we simply use push_back() to add each high score struct to the vector. We aren't doing it that way, because I want you to practice using iterators.

You could sort the scores by simply calling the STL sort() algorithm. I would suggest that you try this out because it's something you should know, but for your submitted program you are required to sort the vector yourself as you did in the earlier high scores assignment, using iterators to access the items in the vector.

If you are using the indexOfLargest() function from the solution to the previous high scores program -- which I encourage -- you may run into some const/non-const difficulties. The function needs to return a regular iterator (so that the calling function can use it to modify the vector). But the vector passed into the function should be const, which means the iterator passed into the vector should be a const_iterator. But that makes it impossible to return a non-const iterator. To solve this we will have to make the second parameter a regular iterator, even though it could be used to modify the const vector.

In your displayData() function you'll need to use const_iterator instead of iterator. See lesson 19.4.

Here is an example that shows how to use an iterator to access a particular member of a struct:

swap((*iter1).firstmember, (*iter2).firstmember); 

This will work just fine, but there is a C++ operator that combines these two (dereference and then select). I works like this:

swap(iter1 -> firstmember, iter2 -> firstmember);

Assignment { 8.2 B} [25 points]

No documentation (commenting) is required on this assignment.

Convert the OrderedPair class, which is provided below, into a templated class. Note that it will only work with types that have the operators + and < and << overloaded. But you should be able to try your templated class out with types string, myString, double, feetInches, and fraction.

Also, create a programmer-defined exception class named "DuplicateMemberError" and add an if statement to each of the two mutators to throw this exception if the precondition has not been met. The precondition is given as a comment in the header file. Notice that you can test your exception handling by entering the same number twice when prompted for two numbers.

Put your class in a namespace named "cs_pairs"

Finally, to show that your class will work with different types, and also to show that you know how to use a templated class as a client, modify the given client file so that it uses your class using int as the type parameter, and then, in the same main(), repeat the code again with a few changes necessary to make it use ordered pairs of strings instead of ordered pairs of ints. One of the things you'll have to change is the generation of the random values for the ordered pairs. Here's what I used:

 string empty = ""; myList2[i].setFirst(empty + char('a' + rand() % 26)); myList2[i].setSecond(empty + char('A' + rand() % 26));

Here is the header file, orderedpair.h. The syntax for declaring a constant in a class may look mysterious. To use constants in a class, we have to declare it inside the class, then assign it a value outside the class, as you'll see below. (That's actually not true for int constants -- they can be assigned inside the class -- but we want our code to be flexible enough to handle different types.)

#include  /* precondition for setFirst and setSecond: the values of first and second cannot be equal, except when they are both equal to DEFAULT_VALUE. */ namespace cs_pairs { class OrderedPair { public: // Use the first of the following two lines to make the non-templated version work. // Use the second one when you begin converting to a templated version. static const int DEFAULT_VALUE = int(); // static const int DEFAULT_VALUE; OrderedPair(int newFirst = DEFAULT_VALUE, int newSecond = DEFAULT_VALUE); void setFirst(int newFirst); void setSecond(int newSecond); int getFirst() const; int getSecond() const; OrderedPair operator+(const OrderedPair& right) const; bool operator<(const OrderedPair& right) const; void print() const; private: int first; int second; }; // Leave the following const declaration commented out when you are testing the non-templated version. // Uncomment it when you begin converting to a templated version. // To convert to a templated version you will need a template prefix here above this declaration // const int OrderedPair::DEFAULT_VALUE = int(); } 

Here is the implementation file, orderedpair.cpp

#include "orderedpair.h" #include  using namespace std; namespace cs_pairs { OrderedPair::OrderedPair(int newFirst, int newSecond) { setFirst(newFirst); setSecond(newSecond); } void OrderedPair::setFirst(int newFirst) { // if statement to throw an exception if precondition not met goes here. first = newFirst; } void OrderedPair::setSecond(int newSecond) { // if statement to throw an exception if precondition not met goes here. second = newSecond; } int OrderedPair::getFirst() const { return first; } int OrderedPair::getSecond() const { return second; } OrderedPair OrderedPair::operator+(const OrderedPair& right) const { return OrderedPair(first + right.first, second + right.second); } bool OrderedPair::operator<(const OrderedPair& right) const { return first + second < right.first + right.second; } void OrderedPair::print() const { cout << "(" << first << ", " << second << ")"; } } 

Here is the client file.

#include  #include  #include  #include "orderedpair.h" using namespace std; using namespace cs_pairs; int main() { int num1, num2; OrderedPair myList[10]; srand(static_cast(time(0))); cout << "default value: "; myList[0].print(); cout << endl; for (int i = 0; i < 10; i++) { myList[i].setFirst(rand() % 50); myList[i].setSecond(rand() % 50 + 50); } myList[2] = myList[0] + myList[1]; if (myList[0] < myList[1]) { myList[0].print(); cout << " is less than "; myList[1].print(); cout << endl; } for (int i = 0; i < 10; i++) { myList[i].print(); cout << endl; } cout << "Enter two numbers to use in an OrderedPair. Make sure they are different numbers: "; cin >> num1 >> num2; OrderedPair x; /* use this before you've implemented the exception handling in the class: */ x.setFirst(num1); x.setSecond(num2); /* use this after you've implemented the exception handling in the class: try { x.setFirst(num1); x.setSecond(num2); } catch (OrderedPair::DuplicateMemberError e) { x.setFirst(0); x.setSecond(0); } */ cout << "The resulting OrderedPair: "; x.print(); cout << endl; }