implement a looking-for-group queue for a game where players can be one of three

ID: 3918391 • Letter: I

Question

implement a looking-for-group queue for a game where players can be one of three roles
(Defender, Hunter, and Bard) and each group consists of one Defender, one Hunter, and one Bard.

Create a new C++ source
file named lfgqueue.cpp that implements the LFGQueue class declared in lfgqueue.h such
that lfqueue.cpp and the provided files compile into a program that runs with no failed tests.

please use the code given below

/////////////////////////////////////////

(lfgqueue.h)

#ifndef LFGQUEUE_H #define LFGQUEUE_H #include "player.h" class LFGQueue { public: // Constructs a new empty queue LFGQueue(); // Returns the number of players in the queue. int size(); // Pushes a pointer to a player onto the back of the queue. void push_player(Player* p); // Returns a pointer to the frontmost player // with the specified role. // If no such player exists, returns nullptr. Player* front_player(Player::Role r); // Removes the frontmost player with the specified role. // If no such player exists, does nothing. void pop_player(Player::Role r); // Returns whether the queue contains a complete group // (a Defender, a Hunter, and a Bard). // // If the queue contains a complete group, the method // sets the first three elements of the array parameter // equal to the addresses of the frontmost: // 1. Defender (index 0) // 2. Hunter (index 1) // 3. Bard (index 2) bool front_group(Player** group); // Removes the frontmost Defender, Hunter, and Bard // from the queue. If some role has no player with that role, // then does nothing. void pop_group(); private: Player** players; int count; int capacity; }; #endif

//////////////////////////////////////////////
(player.h)

#ifndef PLAYER_H #define PLAYER_H #include <string> using namespace std; class Player { public: // This works like a custom type with just four values. // Outside of Player methods, reference them like: // "if (p->role == Player::Defender)", etc. enum Role {Defender, Hunter, Bard}; // Initializes a player with the given name and role Player(string name, Role role); // Returns the name of the player string name(); // Returns the role of the player Role role(); private: string _name; Role _role; }; #endif

///////////////////////////////////////////////////
(player.cpp)

#include "player.h" Player :: Player(string name, Role role) { _name = name; _role = role; } string Player :: name() { return _name; } Player::Role Player :: role() { return _role; }

/////////////////////////////////////////

(main.cpp)

#include <sstream> #include <cstdlib> #include <iostream> #include "lfgqueue.h" using namespace std; inline void _test(const char* expression, const char* file, int line) { cerr << "test(" << expression << ") failed in file " << file; cerr << ", line " << line << "." << endl; abort(); } #define test(EXPRESSION) ((EXPRESSION) ? (void)0 : _test(#EXPRESSION, __FILE__, __LINE__)) int main() { // Variables used for testing Player* group[3]; Player daria("Daria", Player::Defender); Player daniela("Daniela", Player::Defender); Player hector("Hector", Player::Hunter); Player hugo("Hugo", Player::Hunter); Player berta("Berta", Player::Bard); Player bernardo("Bernardo", Player::Bard); // Test size(), add(), front_player(), pop_player() // on a small example. LFGQueue q; test(q.size() == 0); test(q.front_player(Player::Defender) == nullptr); test(q.front_player(Player::Hunter) == nullptr); test(q.front_player(Player::Bard) == nullptr); q.push_player(&daniela); test(q.size() == 1); test(q.front_player(Player::Defender) == &daniela); test(q.front_player(Player::Hunter) == nullptr); test(q.front_player(Player::Bard) == nullptr); q.push_player(&hector); test(q.size() == 2); test(q.front_player(Player::Defender) == &daniela); test(q.front_player(Player::Hunter) == &hector); test(q.front_player(Player::Bard) == nullptr); q.push_player(&berta); test(q.size() == 3); test(q.front_player(Player::Defender) == &daniela); test(q.front_player(Player::Hunter) == &hector); test(q.front_player(Player::Bard) == &berta); q.push_player(&hugo); test(q.size() == 4); test(q.front_player(Player::Defender) == &daniela); test(q.front_player(Player::Hunter) == &hector); test(q.front_player(Player::Bard) == &berta); q.push_player(&bernardo); test(q.size() == 5); test(q.front_player(Player::Defender) == &daniela); test(q.front_player(Player::Hunter) == &hector); test(q.front_player(Player::Bard) == &berta); q.push_player(&daria); test(q.size() == 6); test(q.front_player(Player::Defender) == &daniela); test(q.front_player(Player::Hunter) == &hector); test(q.front_player(Player::Bard) == &berta); // Order is now [Daniela, Hector, Berta, Hugo, Bernardo, Daria] q.pop_player(Player::Defender); test(q.size() == 5); test(q.front_player(Player::Defender) == &daria); test(q.front_player(Player::Hunter) == &hector); test(q.front_player(Player::Bard) == &berta); q.pop_player(Player::Hunter); test(q.size() == 4); test(q.front_player(Player::Defender) == &daria); test(q.front_player(Player::Hunter) == &hugo); test(q.front_player(Player::Bard) == &berta); q.pop_player(Player::Bard); test(q.size() == 3); test(q.front_player(Player::Defender) == &daria); test(q.front_player(Player::Hunter) == &hugo); test(q.front_player(Player::Bard) == &bernardo); q.pop_player(Player::Bard); test(q.size() == 2); test(q.front_player(Player::Defender) == &daria); test(q.front_player(Player::Hunter) == &hugo); test(q.front_player(Player::Bard) == nullptr); q.pop_player(Player::Defender); test(q.size() == 1); test(q.front_player(Player::Defender) == nullptr); test(q.front_player(Player::Hunter) == &hugo); test(q.front_player(Player::Bard) == nullptr); q.pop_player(Player::Hunter); test(q.size() == 0); test(q.front_player(Player::Defender) == nullptr); test(q.front_player(Player::Hunter) == nullptr); test(q.front_player(Player::Bard) == nullptr); // Test previous methods plus front_group(), pop_group() on a small example. q.push_player(&hugo); test(q.size() == 1); test(q.front_player(Player::Defender) == nullptr); test(q.front_player(Player::Hunter) == &hugo); test(q.front_player(Player::Bard) == nullptr); test(!q.front_group(group)); q.pop_group(); test(q.size() == 1); test(q.front_player(Player::Defender) == nullptr); test(q.front_player(Player::Hunter) == &hugo); test(q.front_player(Player::Bard) == nullptr); q.push_player(&hector); test(q.size() == 2); test(q.front_player(Player::Defender) == nullptr); test(q.front_player(Player::Hunter) == &hugo); test(q.front_player(Player::Bard) == nullptr); test(!q.front_group(group)); q.pop_group(); test(q.size() == 2); test(q.front_player(Player::Defender) == nullptr); test(q.front_player(Player::Hunter) == &hugo); test(q.front_player(Player::Bard) == nullptr); q.push_player(&berta); test(q.size() == 3); test(q.front_player(Player::Defender) == nullptr); test(q.front_player(Player::Hunter) == &hugo); test(q.front_player(Player::Bard) == &berta); test(!q.front_group(group)); q.pop_group(); test(q.size() == 3); test(q.front_player(Player::Defender) == nullptr); test(q.front_player(Player::Hunter) == &hugo); test(q.front_player(Player::Bard) == &berta); q.push_player(&bernardo); test(q.size() == 4); test(q.front_player(Player::Defender) == nullptr); test(q.front_player(Player::Hunter) == &hugo); test(q.front_player(Player::Bard) == &berta); test(!q.front_group(group)); q.pop_group(); test(q.size() == 4); test(q.front_player(Player::Defender) == nullptr); test(q.front_player(Player::Hunter) == &hugo); test(q.front_player(Player::Bard) == &berta); q.push_player(&daria); test(q.size() == 5); test(q.front_player(Player::Defender) == &daria); test(q.front_player(Player::Hunter) == &hugo); test(q.front_player(Player::Bard) == &berta); test(q.front_group(group)); q.push_player(&daniela); test(q.size() == 6); test(q.front_player(Player::Defender) == &daria); test(q.front_player(Player::Hunter) == &hugo); test(q.front_player(Player::Bard) == &berta); test(q.front_group(group)); // Order is now [Hugo, Hector, Berta, Bernardo, Daria, Daniela] group[0] = group[1] = group[2] = nullptr; test(q.front_group(group)); test(group[0] == &daria); test(group[1] == &hugo); test(group[2] == &berta); q.pop_group(); test(q.size() == 3); test(q.front_player(Player::Defender) == &daniela); test(q.front_player(Player::Hunter) == &hector); test(q.front_player(Player::Bard) == &bernardo); group[0] = group[1] = group[2] = nullptr; test(q.front_group(group)); test(group[0] == &daniela); test(group[1] == &hector); test(group[2] == &bernardo); q.pop_group(); test(q.size() == 0); test(q.front_player(Player::Defender) == nullptr); test(q.front_player(Player::Hunter) == nullptr); test(q.front_player(Player::Bard) == nullptr); // Test a set of 999 players: 333 of each role in the following order: // 333 defenders, 1 hunter, 1 bard, 1 hunter, 1 bard... // Create the players Player** players = new Player*[999]; ostringstream oss; for (int i = 0; i < 333; ++i) { oss.str(""); oss << "Defender #" << i+1; players[i] = new Player(oss.str(), Player::Defender); } for (int i = 333; i < 999; i+=2) { oss.str(""); oss << "Hunter #" << (i-333)/2+1; players[i] = new Player(oss.str(), Player::Hunter); } for (int i = 334; i < 999; i+=2) { oss.str(""); oss << "Bard #" << (i-334)/2+1; players[i] = new Player(oss.str(), Player::Bard); } // Add them to the queue for (int i = 0; i < 999; ++i) q.push_player(players[i]); test(q.size() == 999); // Repeatedly check and remove the frontmost players. // Because of how we scrambled, this has a fixed order. for (int i = 0; i < 333; ++i) { group[0] = group[1] = group[2] = nullptr; test(q.front_group(group)); oss.str(""); oss << "Defender #" << i+1; test(group[0]->name() == oss.str()); oss.str(""); oss << "Hunter #" << i+1; test(group[1]->name() == oss.str()); oss.str(""); oss << "Bard #" << i+1; test(group[2]->name() == oss.str()); q.pop_group(); test(q.size() == 999 - 3 * (i+1)); } test(q.size() == 0); test(!q.front_group(group)); for (int i = 0; i < 999; ++i) delete players[i]; delete[] players; cout << "Assignment complete." << endl; }

capacity Player** A count Player* array "Berta"" Hunter Hector""Daria" Bard Defender Player objects Figure 1: A queue of players.

Explanation / Answer

//lfgqueue.h

#ifndef LFGQUEUE_H

#define LFGQUEUE_H

#include"player.h"

class LFGQueue {

public:

// Constructs a new empty queue

LFGQueue();

// Returns the number of players in the queue.

int size();

// Pushes a pointer to a player onto the back of the queue.

void push_player(Player* p);

// Returns a pointer to the frontmost player

// with the specified role.

// If no such player exists, returns nullptr.

Player* front_player(Player::Role r);

// Removes the frontmost player with the specified role.

// If no such player exists, does nothing.

void pop_player(Player::Role r);

// Returns whether the queue contains a complete group

// (a Defender, a Hunter, and a Bard).

// // If the queue contains a complete group, the method

// sets the first three elements of the array parameter

// equal to the addresses of the frontmost:

// 1. Defender (index 0) // 2. Hunter (index 1) // 3. Bard (index 2)

bool front_group(Player** group);

// Removes the frontmost Defender, Hunter, and Bard // from the queue. If some role has no player with that role,

// then does nothing.

void pop_group();

private:

Player** players;

int count;

int capacity;

}

#endif

//lfgqueue.cpp

#include "lfgqueue.h"

LFGQueue::LFGQueue()

{

this->count = 0;

this->capacity = 0;

this->players = new Player*[10];

}

int LFGQueue::size()

{

return this->count;

}

void LFGQueue::push_player(Player * p)

{

if (this->count <= this->capacity) {

players[this->count] = p;

this->count++;

}

Player * LFGQueue::front_player(Player::Role r)

{

for (int i = 0; i < size(); i++) {

for (int j = 0; j < 3; j++) {

if ( players[i][j].role == r) {

return players[i];

}

return nullptr;

}

void LFGQueue::pop_player(Player::Role r)

{

int idx = 0;

for (int i = 0; i < size(); i++) {

for (int j = 0; j < 3; j++) {

if (players[i][j].role == r) {

idx = i;

}

for (int j = idx; j < size() -1; j++) {

players[j] = players[j + 1];

}

bool LFGQueue::front_group(Player ** group)

{

bool isDefenderPresent=false, isHunterPresent=false, isBardPresent=false;

for (int i = 0; i < size(); i++) {

for (int j = 0; j < 3; j++) {

if (!isDefenderPresent && players[i][j].role == Player::Role::Defender) {

isDefenderPresent = true;

}

for (int j = 0; j < 3; j++) {

if (!isHunterPresent && players[i][j].role == Player::Role::Hunter) {

isHunterPresent = true;

}

for (int j = 0; j < 3; j++) {

if (!isBardPresent && players[i][j].role == Player::Role::Bard) {

isBardPresent = true;

}

if (isDefenderPresent && isHunterPresent && isBardPresent)

return true;

else

return false;

}

void LFGQueue::pop_group()

{

pop_player(Player::Defender);

pop_player(Player::Hunter);

pop_player(Player::Bard);

}

//player.h

#ifndef PLAYER_H

#define PLAYER_H

#include <string>

using namespace std;

class Player {

public:

// This works like a custom type with just four values.

// Outside of Player methods, reference them like:

// "if (p->role == Player::Defender)", etc.

enum Role {Defender, Hunter, Bard};

// Initializes a player with the given name and role

Player(string name, Role role);

// Returns the name of the player

string name();

// Returns the role of the player

Role role();

private:

string _name;

Role _role;

};

#endif

//player.cpp

#include "player.h"

Player :: Player(string name, Role role) {

_name = name; _role = role;

}

string Player :: name() {

return _name;

}

Player::Role Player :: role() {

return _role;

}

//main.cpp

#include <sstream>

#include <cstdlib>

#include <iostream>

#include"lfgqueue.h"

using namespace std;

inline void _test(const char* expression, const char* file, int line) {

std::cerr << "test(" << expression << ") failed in file " << file;

std::cerr << ", line " << line << "." << std::endl;

abort();

}

#define test(EXPRESSION) ((EXPRESSION) ? (void)0 : _test(#EXPRESSION, __FILE__, __LINE__))

int main() {

// Variables used for testing

Player* group[3];

Player daria("Daria", Player::Defender);

Player daniela("Daniela", Player::Defender);

Player hector("Hector", Player::Hunter);

Player hugo("Hugo", Player::Hunter);

Player berta("Berta", Player::Bard);

Player bernardo("Bernardo", Player::Bard);

// Test size(), add(), front_player(), pop_player() // on a small example.

LFGQueue q;

test(q.size() == 0);

test(q.front_player(Player::Defender) == nullptr);

test(q.front_player(Player::Hunter) == nullptr);

test(q.front_player(Player::Bard) == nullptr);

q.push_player(&daniela); test(q.size() == 1);