1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
|
// FILE: bag4.h (part of the namespace main_savitch_6A)
// TEMPLATE CLASS PROVIDED: bag<item>
//
// TEMPLATE PARAMETER, TYPEDEFS and MEMBER CONSTANTS for the bag<Item> class:
// The template parameter, Item, is the data type of the items in the bag,
// also defined as bag<Item>::value_type. 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). The definition bag<Item>::size_type is the data type
// of any variable that keeps track of how many items are in a bag. The static
// const DEFAULT_CAPACITY is the initial capacity of a bag created by the
// default constructor.
// NOTE:
// Many compilers require the use of the new keyword typename before using
// the expressions bag<Item>::value_type and bag<Item>::size_type. Otherwise
// the compiler doesn't have enough information to realize that it is the
// name of a data type.
//
// CONSTRUCTOR for the bag<Item> template class:
// bag(size_type initial_capacity = DEFAULT_CAPACITY)
// Postcondition: The bag is empty with an initial capacity given by the
// parameter. The insert function will work efficiently (without allocating
// new memory) until this capacity is reached.
//
// MODIFICATION MEMBER FUNCTIONS for the bag<Item> template class:
// size_type erase(const Item& 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).
//
// bool erase_one(const Item& target)
// Postcondition: If target was in the bag, then one copy of target 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 Item& entry)
// Postcondition: A new copy of entry has been added to the bag.
//
// void operator +=(const bag<Item>& addend)
// Postcondition: Each item in addend has been added to this bag.
//
// void reserve(size_type new_capacity)
// Postcondition: The bag's current capacity is changed to new_capacity
// (but not less than the number of items currently in the bag). The insert
// function will work efficiently without allocating new memory) until the
// capacity is reached.
//
// CONSTANT MEMBER FUNCTIONS for the bag<Item> template class:
// size_type count(const Item& target) const
// Postcondition: Return value is number of times target is in the bag.
//
// Item grab( ) const
// Precondition: size( ) > 0
// Postcondition: The return value is a randomly selected item from the bag.
//
// size_type size( ) const
// Postcondition: The return value is the total number of items in the bag.
//
// NONMEMBER FUNCTIONS for the bag<Item> template class:
// template <class Item>
// bag<Item> operator +(const bag<Item>& b1, const bag<Item>& b2)
// Postcondition: The bag returned is the union of b1 and b2.
//
// VALUE SEMANTICS for the bag<Item> template class:
// Assignments and the copy constructor may be used with bag objects.
//
// DYNAMIC MEMORY USAGE by the bag<Item> template class:
// If there is insufficient dynamic memory, then the following functions call
// new_handler: the constructors, resize, insert, operator += , operator +,
// and the assignment operator.
#ifndef MAIN_SAVITCH_BAG4_H
#define MAIN_SAVITCH_BAG4_H
#include <cstdlib> // Provides size_t
namespace main_savitch_6A
{
template <class Item>
class bag
{
public:
// TYPEDEFS and MEMBER CONSTANTS
typedef Item value_type;
typedef std::size_t size_type;
static const size_type DEFAULT_CAPACITY = 30;
// CONSTRUCTORS and DESTRUCTOR
bag(size_type initial_capacity = DEFAULT_CAPACITY);
bag(const bag& source);
~bag( );
// MODIFICATION MEMBER FUNCTIONS
size_type erase(const Item& target);
bool erase_one(const Item& target);
void insert(const Item& entry);
void operator =(const bag& source);
void operator +=(const bag& addend);
void reserve(size_type capacity);
// CONSTANT MEMBER FUNCTIONS
size_type count(const Item& target) const;
Item grab( ) const;
size_type size( ) const { return used; }
private:
Item *data; // Pointer to partially filled dynamic array
size_type used; // How much of array is being used
size_type capacity; // Current capacity of the bag
};
// NONMEMBER FUNCTIONS
template <class Item>
bag<Item> operator +(const bag<Item>& b1, const bag<Item>& b2);
}
#include "bag4.template" // Include the implementation
#endif
|