1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/algs4-c++/src/Queue.cpp	Fri May 29 21:13:32 2015 -0500
     1.3 @@ -0,0 +1,159 @@
     1.4 +// g++ -D QUEUE_MAIN -std=c++0x Queue.cpp
     1.5 +// g++ -D QUEUE_MAIN -std=c++11 Queue.cpp
     1.6 +
     1.7 +
     1.8 +#include "Queue.hpp"
     1.9 +
    1.10 +#include <cassert>
    1.11 +#include <cstddef>
    1.12 +
    1.13 +#include <iostream>
    1.14 +
    1.15 +template <typename T>
    1.16 +Queue<T>::Queue( void ) :
    1.17 +    N (0),
    1.18 +    first (nullptr),
    1.19 +    last (nullptr)
    1.20 +    {
    1.21 +    }
    1.22 +    
    1.23 +template <typename T>
    1.24 +Queue<T>::~Queue( void ) {
    1.25 +    assert( N == 0 );  // Catch the potential memory leak.
    1.26 +    while ( first ) {
    1.27 +        Node *next = first->next;
    1.28 +        delete first;
    1.29 +        first = next;
    1.30 +        }
    1.31 +    }
    1.32 +
    1.33 +template <typename T>
    1.34 +void Queue<T>::enqueue( T &item ) {
    1.35 +    Node * node = new Node();
    1.36 +    node->item = item;
    1.37 +    node->next = nullptr;
    1.38 +
    1.39 +    if ( last ) {
    1.40 +        last->next = node;
    1.41 +        last = node;
    1.42 +        }
    1.43 +    else {
    1.44 +        last = first = node;
    1.45 +        }
    1.46 +
    1.47 +    N++;
    1.48 +    }
    1.49 +
    1.50 +template <typename T>
    1.51 +T Queue<T>::dequeue( void ) {
    1.52 +    assert( N > 0 );
    1.53 +
    1.54 +    T item = first->item;
    1.55 +
    1.56 +    Node *old = first;
    1.57 +    first = first->next;
    1.58 +    delete old;
    1.59 +    N--;
    1.60 +
    1.61 +    if ( ! first )
    1.62 +        last = nullptr;
    1.63 +
    1.64 +    return item;
    1.65 +    }
    1.66 +
    1.67 +template <typename T>
    1.68 +bool Queue<T>::is_empty( void ) {
    1.69 +    return N == 0;
    1.70 +    }
    1.71 +
    1.72 +template <typename T>
    1.73 +size_t Queue<T>::size( void ) {
    1.74 +    return N;
    1.75 +    }
    1.76 +
    1.77 +template <typename T>
    1.78 +typename Queue<T>::iterator Queue<T>::begin( void ) {
    1.79 +    return Queue<T>::iterator( first );
    1.80 +    }
    1.81 +
    1.82 +template <typename T>
    1.83 +typename Queue<T>::iterator Queue<T>::end( void ) {
    1.84 +    return Queue<T>::iterator( nullptr );
    1.85 +    }
    1.86 +
    1.87 +
    1.88 +////////////////////////////////////////////////////////////////////////////////
    1.89 +
    1.90 +template <typename T>
    1.91 +Queue<T>::iterator::iterator( Node *c ) :
    1.92 +    curr (c)
    1.93 +    {
    1.94 +    }
    1.95 +
    1.96 +template <typename T>
    1.97 +typename Queue<T>::iterator & Queue<T>::iterator::operator++() {
    1.98 +    if ( this->curr != nullptr ) {
    1.99 +        this->curr = this->curr->next;
   1.100 +        }
   1.101 +    return *this;
   1.102 +    }
   1.103 +
   1.104 +template <typename T>
   1.105 +typename Queue<T>::iterator Queue<T>::iterator::operator++( int ) {
   1.106 +    auto t = Queue<T>::iterator( *this );
   1.107 +
   1.108 +    if ( this->curr != nullptr ) {
   1.109 +        this->curr = this->curr->next;
   1.110 +        }
   1.111 +    return t;
   1.112 +    }
   1.113 +
   1.114 +template <typename T>
   1.115 +T Queue<T>::iterator::operator*() {
   1.116 +    return this->curr->item;
   1.117 +    }
   1.118 +
   1.119 +template <typename T>
   1.120 +bool Queue<T>::iterator::operator!=( typename Queue<T>::iterator other ) {
   1.121 +    return this->curr != other.curr;
   1.122 +    }
   1.123 +
   1.124 +
   1.125 +////////////////////////////////////////////////////////////////////////////////
   1.126 +
   1.127 +#ifdef QUEUE_MAIN
   1.128 +
   1.129 +#include <iostream>
   1.130 +
   1.131 +int main ( int argc, char **argv ) {
   1.132 +
   1.133 +    Queue<long> queue;
   1.134 +
   1.135 +    long i;
   1.136 +    while ( ! std::cin.eof() ) {
   1.137 +        std::cin >> i;
   1.138 +        if ( std::cin.good() ) 
   1.139 +            if ( i >= 0 )
   1.140 +                queue.enqueue(i);
   1.141 +            else
   1.142 +                queue.dequeue();
   1.143 +        }
   1.144 +
   1.145 +    std::cout << "Queue has " << queue.size() << " entries." << std::endl;
   1.146 +
   1.147 +    for ( auto iter = queue.begin(); iter != queue.end(); ++iter ) {
   1.148 +        std::cout << *iter << std::endl;
   1.149 +        }
   1.150 +
   1.151 +    std::cout << "Dequeuing entries..." << std::endl;
   1.152 +
   1.153 +    while ( ! queue.is_empty() ) {
   1.154 +        i = queue.dequeue();
   1.155 +        std::cout << i << std::endl;
   1.156 +        }
   1.157 +
   1.158 +    std::cout << "Queue has " << queue.size() << " entries." << std::endl;
   1.159 +
   1.160 +    }
   1.161 +
   1.162 +#endif

     2.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     2.2 +++ b/algs4-c++/src/Queue.hpp	Fri May 29 21:13:32 2015 -0500
     2.3 @@ -0,0 +1,66 @@
     2.4 +#ifndef QUEUE_HPP
     2.5 +#define QUEUE_HPP
     2.6 +
     2.7 +#include <cstddef>
     2.8 +
     2.9 +// Linked list based queue after Sedgewick and Wayne, Algorithms 4th ed, Algorithm 1.3
    2.10 +
    2.11 +template <typename T>
    2.12 +class Queue {
    2.13 +
    2.14 +public:
    2.15 +
    2.16 +    ////////////////////////////////////
    2.17 +    class Node {
    2.18 +    public:
    2.19 +        T item;
    2.20 +        Node *next;
    2.21 +        };
    2.22 +
    2.23 +
    2.24 +    ////////////////////////////////////
    2.25 +    class iterator;
    2.26 +    friend class iterator;
    2.27 +    class iterator {
    2.28 +
    2.29 +    public:
    2.30 +
    2.31 +        iterator( Node *c );
    2.32 +
    2.33 +        iterator& operator++();
    2.34 +        iterator operator++(int);
    2.35 +
    2.36 +        T operator*();
    2.37 +        bool operator!=( typename Queue<T>::iterator );
    2.38 +
    2.39 +    private:
    2.40 +
    2.41 +        Node *curr;
    2.42 +        };
    2.43 +
    2.44 +    ////////////////////////////////////
    2.45 +
    2.46 +    Queue( void );
    2.47 +    ~Queue( void );
    2.48 +
    2.49 +    void enqueue( T &item );
    2.50 +    T dequeue( void );
    2.51 +
    2.52 +    bool is_empty( void );
    2.53 +    size_t size( void );
    2.54 +
    2.55 +    iterator begin( void );
    2.56 +    iterator end( void );
    2.57 +
    2.58 +private:
    2.59 +
    2.60 +    size_t N;
    2.61 +    Node *first;
    2.62 +    Node *last;
    2.63 +
    2.64 +    };
    2.65 +
    2.66 +
    2.67 +
    2.68 +#endif
    2.69 +