dlib C++ Library - queue_ex.cpp

// The contents of this file are in the public domain. See LICENSE_FOR_EXAMPLE_PROGRAMS.txt
/*
 This is an example illustrating the use of the queue component (and 
 to some degree the general idea behind most of the other container 
 classes) from the dlib C++ Library.
 It loads a queue with 20 random numbers. Then it uses the enumerable 
 interface to print them all to the screen. Then it sorts the numbers and 
 prints them to the screen.
*/
#include <dlib/queue.h>
#include <iostream>
#include <iomanip>
#include <ctime>
#include <cstdlib>
// I'm picking the version of the queue that is kernel_2a extended by
// the queue sorting extension. This is just a normal queue but with the
// added member function sort() which sorts the queue.
typedef dlib::queue<int>::sort_1b_c queue_of_int;
using namespace std;
using namespace dlib;
int main()
{
 queue_of_int q;
 // initialize rand()
 srand(time(0));
 for (int i = 0; i < 20; ++i)
 {
 int a = rand()&0xFF;
 // note that adding a to the queue "consumes" the value of a because
 // all container classes move values around by swapping them rather
 // than copying them. So a is swapped into the queue which results 
 // in a having an initial value for its type (for int types that value
 // is just some undefined value. )
 q.enqueue(a);
 }
 cout << "The contents of the queue are:\n";
 while (q.move_next())
 cout << q.element() << " ";
 cout << "\n\nNow we sort the queue and its contents are:\n";
 q.sort(); // note that we don't have to call q.reset() to put the enumerator
 // back at the start of the queue because calling sort() does
 // that automatically for us. (In general, modifying a container
 // will reset the enumerator).
 while (q.move_next())
 cout << q.element() << " "; 
 cout << "\n\nNow we remove the numbers from the queue:\n";
 while (q.size() > 0)
 {
 int a;
 q.dequeue(a);
 cout << a << " ";
 }
 cout << endl;
}