Problem: A) Fix any errors to get the following program to run in your environment. B) The header file seems well documented, but add any comments that you think may help new C++ programmers. C) Document the class implementation file to explain the algorithms used in each function to achieve the intended postcondition. D) Document the test program. E) Write your own test program to display the results of the implemented functions. Be sure to document your test program F) Write a summary of what your test program fully tests the bag class. Include a copy of the output after your summary.

G) Answer the following questions about the original code.

1) Are all member functions defined in the implementation file? If not, explain why the code still works.

2) Are all member and non-member functions tested by the original test program? If not, list those that were not tested.

3) Why do you think the namespace main_savitch code was used? Can the code be made to work without this code?

// FILE: bag1.h // CLASS PROVIDED: bag (part of the namespace main_savitch_3) // // TYPEDEF and MEMBER CONSTANTS for the bag class: // typedef ____ value_type // bag::value_type is the data type of the items in the bag. It may be any of // the C++ built-in types (int, char, etc.), or a class with a default // constructor, an assignment operator, and operators to // test for equality (x == y) and non-equality (x != y). // // typedef ____ size_type // bag::size_type is the data type of any variable that keeps track of how many items // are in a bag. // // static const size_type CAPACITY = _____ // bag::CAPACITY is the maximum number of items that a bag can hold. // // CONSTRUCTOR for the bag class: // bag( ) // Postcondition: The bag has been initialized as an empty bag. // // MODIFICATION MEMBER FUNCTIONS for the bag class: // size_type erase(const value_type& target); // Postcondition: All copies of target have been removed from the bag. // The return value is the number of copies removed (which could be zero). // // void erase_one(const value_type& target) // Postcondition: If target was in the bag, then one copy has been removed; // otherwise the bag is unchanged. A true return value indicates that one // copy was removed; false indicates that nothing was removed. // // void insert(const value_type& entry) // Precondition: size( ) < CAPACITY. // Postcondition: A new copy of entry has been added to the bag. // // void operator +=(const bag& addend) // Precondition: size( ) + addend.size( ) <= CAPACITY. // Postcondition: Each item in addend has been added to this bag. // // CONSTANT MEMBER FUNCTIONS for the bag class: // size_type size( ) const // Postcondition: The return value is the total number of items in the bag. // // size_type count(const value_type& target) const // Postcondition: The return value is number of times target is in the bag. // // NONMEMBER FUNCTIONS for the bag class: // bag operator +(const bag& b1, const bag& b2) // Precondition: b1.size( ) + b2.size( ) <= bag::CAPACITY. // Postcondition: The bag returned is the union of b1 and b2. // // VALUE SEMANTICS for the bag class: // Assignments and the copy constructor may be used with bag objects. #ifndef MAIN_SAVITCH_BAG1_H #define MAIN_SAVITCH_BAG1_H #include // Provides size_t namespace main_savitch_3 { class bag { public: // TYPEDEFS and MEMBER CONSTANTS typedef int value_type; typedef std::size_t size_type; static const size_type CAPACITY = 30; // CONSTRUCTOR bag( ) { used = 0; } // MODIFICATION MEMBER FUNCTIONS size_type erase(const value_type& target); bool erase_one(const value_type& target); void insert(const value_type& entry); void operator +=(const bag& addend); // CONSTANT MEMBER FUNCTIONS size_type size( ) const { return used; } size_type count(const value_type& target) const; private: value_type data[CAPACITY]; // The array to store items size_type used; // How much of array is used }; // NONMEMBER FUNCTIONS for the bag class bag operator +(const bag& b1, const bag& b2); } #endif

// FILE: bag1.cpp // CLASS IMPLEMENTED: bag (see bag1.h for documentation) // INVARIANT for the bag class: // 1. The number of items in the bag is in the member variable used; // 2. For an empty bag, we do not care what is stored in any of data; for a // non-empty bag the items in the bag are stored in data[0] through // data[used-1], and we don't care what's in the rest of data. #include // Provides copy function #include // Provides assert function #include "bag1.h" using namespace std; namespace main_savitch_3 { const bag::size_type bag::CAPACITY; bag::size_type bag::erase(const value_type& target) { size_type index = 0; size_type many_removed = 0; while (index < used) { if (data[index] == target) { --used; data[index] = data[used]; ++many_removed; } else ++index; } return many_removed; } bool bag::erase_one(const value_type& target) { size_type index; // The location of target in the data array // First, set index to the location of target in the data array, // which could be as small as 0 or as large as used-1. If target is not // in the array, then index will be set equal to used. index = 0; while ((index < used) && (data[index] != target)) ++index; if (index == used) return false; // target isnt in the bag, so no work to do. // When execution reaches here, target is in the bag at data[index]. // So, reduce used by 1 and copy the last item onto data[index]. --used; data[index] = data[used]; return true; } void bag::insert(const value_type& entry) // Library facilities used: cassert { assert(size( ) < CAPACITY); data[used] = entry; ++used; } void bag::operator +=(const bag& addend) // Library facilities used: algorithm, cassert { assert(size( ) + addend.size( ) <= CAPACITY); copy(addend.data, addend.data + addend.used, data + used); used += addend.used; } bag::size_type bag::count(const value_type& target) const { size_type answer; size_type i; answer = 0; for (i = 0; i < used; ++i) if (target == data[i]) ++answer; return answer; } bag operator +(const bag& b1, const bag& b2) // Library facilities used: cassert { bag answer; assert(b1.size( ) + b2.size( ) <= bag::CAPACITY); answer += b1; answer += b2; return answer; } }

// FILE: bag_demo.cpp // This is a small demonstration program showing how the bag class is used. #include // Provides cout and cin #include // Provides EXIT_SUCCESS #include "bag1.h" // With value_type defined as an int using namespace std; using namespace main_savitch_3; // PROTOTYPES for functions used by this demonstration program: void get_ages(bag& ages); // Postcondition: The user has been prompted to type in the ages of family // members. These ages have been read and placed in the ages bag, stopping // when the bag is full or when the user types a negative number. void check_ages(bag& ages); // Postcondition: The user has been prompted to type in the ages of family // members once again. Each age is removed from the ages bag when it is typed, // stopping when the bag is empty. int main( ) { bag ages; get_ages(ages); check_ages(ages); cout << "May your family live long and prosper." << endl; return EXIT_SUCCESS; } void get_ages(bag& ages) { int user_input; cout << "Type the ages in your family." << endl; cout << "Type a negative number when you are done:" << endl; cin >> user_input; while (user_input >= 0) { if (ages.size( ) < ages.CAPACITY) ages.insert(user_input); else cout << "I have run out of room and cant add that age." << endl; cin >> user_input; } } void check_ages(bag& ages) { int user_input; cout << "Type those ages again. Press return after each age:" << endl; while (ages.size( ) > 0) { cin >> user_input; if (ages.erase_one(user_input)) cout << "Yes, I've got that age and will remove it." << endl; else cout << "No, that age does not occur!" << endl; } }