dlib/examples/queue_ex.cpp

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2.0 KiB
C++
Executable File

/*
This is an example illustrating the use of the queue component (and
to some degree the generial 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;
}