Test it as you add each new operation When youre done use th

Test it as you add each new operation. When you\'re done, use the program Qtester.cpp to test your class.

1. <<                          Overload the output operator << so that a statement of the form cout << q; will display q\'s

                                                contents from front to back.)

2. size() //returns the number of elements in the queue

3. back() // returns the element at the back of a queue

/*

    tester.cpp

Program to test class Queue.

Input (keyboard): Commands entered by the user.

Output (screen): List of commands and messages describing

                    the effects of each command.

----------------------------------------------------------------*/

#include \"Queue.h\"

#include <iostream>

#include <cctype>

using namespace std;

/*--------------------------------------------------------------

Function to list the available commands.

Output (screen): List of commands.

----------------------------------------------------------------*/

void ShowCommands()

{

cout << \"Use the following commands to test the Queue class:\ \"

       << \"a --- add an element to the queue\ \"

       << \"d --- display contents of queue\ \"

       << \"e --- test whether a queue is empty\ \"

       << \"f --- retrieve the item at the front of the queue\ \"

       << \"h --- help -- print this list of commands\ \"

       << \"r --- remove item from front of the queue\ \"

       << \"s --- display the size of queue\ \"

       << \"b --- retrieve the item at the back of the queue\ \"

       << \"q --- quit testing\ \";

}

int main()

{

QueueElement item;      // item to add to the queue

char command;           // user command (selected from menu)

Queue q;                // The QUEUE

ShowCommands();

do

{

    cout << \"Command? \";

    cin >> command;

    if (isupper(command)) command = tolower(command);

    switch(command)

    {

    case \'a\':

             cout << \"Enter item to add to queue: \";

             cin >> item;

             q.enqueue(item);

             cout << \"--> \" << item << \" added\ \";

             break;

    case \'d\':

             cout << \"--> Queue contents:\ \" << q << endl;

             break;

    case \'e\':

             cout << \"--> Queue \" << (q.empty() ? \"is\" : \"is not\")

                  << \" empty\ \";

             break;

    case \'f\':

             cout << \"--> \" << q.front() << \" is at the front\ \";

    case \'h\':

             ShowCommands();

             break;

    case \'r\':

             q.dequeue();

             cout << \"--> Front element removed\ \";

             break;

    case \'s\':

             cout << \"--> the size of the queue is: \" << q.size() << endl;

             break;

    case \'b\':

             cout << \"--> \" << q.back() << \" is at the back\ \";

             break;

    case \'q\':

             cout << \"--> End of test\ \";

             break;

    default:

             cout << \"*** Illegal command: \" << command << endl;

    }

}

while (command != \'q\');

}

Solution

B and C are correct.

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