#include #include #include #include using namespace std; struct city { string name; // name of the city city *next; // pointer to the next city int numberMessages; // how many messages passed through this city string message; // message we are sending accross }; city* addCity(city *head, city *previous, string cityName ); city* deleteCity(city *head, string cityName); city* deleteEntireNetwork(city *head); city* searchNetwork(city *head, string cityName); city* loadDefaultSetup(city *head); void transmitMsg(city *head, string receiver, string filename); void printPath(city *head); void displayMenu(); city* handleUserInput(city *head); /* Do NOT modify main function */ int main(int argc, char* argv[]) { // pointer to the head of our network of cities city *head = NULL; head = handleUserInput(head); printPath(head); head = deleteEntireNetwork(head); if (head == NULL) cout << \"Path cleaned\" << endl; else printPath(head); cout << \"Goodbye!\" << endl; return 0; } /* * Purpose: handle the interaction with the user * Do NOT modify */ city* handleUserInput(city *head) { bool quit = false; string s_input; int input; // loop until the user quits while (!quit) { displayMenu(); // read in input, assuming a number comes in getline(cin, s_input); input = stoi(s_input); switch (input) { // print all nodes case 1: //rebuild network head = loadDefaultSetup(head); printPath(head); break; case 2: // print path printPath(head); break; case 3: //message is read in from file { string cityReceiver; cout << \"Enter name of the city to receive the message: \" << endl; getline(cin, cityReceiver); cout << \"Enter the message to send: \" << endl; string message; getline(cin, message); transmitMsg(head, cityReceiver, message); } break; case 4: { string newCityName; string prevCityName; cout << \"Enter a new city name: \" << endl; getline(cin, newCityName); cout << \"Enter the previous city name (or First): \" << endl; getline(cin, prevCityName); // find the node containing prevCity city *tmp = NULL; if(prevCityName !=\"First\") tmp = searchNetwork(head, prevCityName); // add the new node head = addCity(head, tmp, newCityName); printPath(head); } break; case 5: // delete city { string city; cout << \"Enter a city name: \" << endl; getline(cin, city); head = deleteCity(head, city); printPath(head); } break; case 6: // delete network head = deleteEntireNetwork(head); break; case 7: // quit quit = true; cout << \"Quitting... cleaning up path: \" << endl; break; default: // invalid input cout << \"Invalid Input\" << endl; break; } } return head; } /* * Purpose: Add a new city to the network * between the city *previous and the city that follows it in the network. */ city* addCity(city *head, city *previous, string cityName ) { city* add = new city; //to distinguish and create the new node, i named it add add->name = cityName; city* tmp = new city; tmp=head; if(previous == NULL){ add->next = head; head = add; } while(tmp != NULL && previous != tmp){ tmp = tmp->next; } if(tm.

1. #include
#include
#include
#include
using namespace std;
struct city
{
string name; // name of the city
city *next; // pointer to the next city
int numberMessages; // how many messages passed through this city
string message; // message we are sending accross
};
city* addCity(city *head, city *previous, string cityName );
city* deleteCity(city *head, string cityName);
city* deleteEntireNetwork(city *head);
city* searchNetwork(city *head, string cityName);
city* loadDefaultSetup(city *head);
void transmitMsg(city *head, string receiver, string filename);
void printPath(city *head);
void displayMenu();
city* handleUserInput(city *head);
/* Do NOT modify main function */
int main(int argc, char* argv[])
{
// pointer to the head of our network of cities
city *head = NULL;
head = handleUserInput(head);
printPath(head);
head = deleteEntireNetwork(head);
if (head == NULL)
cout << "Path cleaned" << endl;
else
printPath(head);
cout << "Goodbye!" << endl;

2. return 0;
}
/*
* Purpose: handle the interaction with the user
* Do NOT modify
*/
city* handleUserInput(city *head)
{
bool quit = false;
string s_input;
int input;
// loop until the user quits
while (!quit)
{
displayMenu();
// read in input, assuming a number comes in
getline(cin, s_input);
input = stoi(s_input);
switch (input)
{
// print all nodes
case 1: //rebuild network
head = loadDefaultSetup(head);
printPath(head);
break;
case 2: // print path
printPath(head);
break;
case 3: //message is read in from file
{
string cityReceiver;
cout << "Enter name of the city to receive the message: " << endl;
getline(cin, cityReceiver);
cout << "Enter the message to send: " << endl;
string message;
getline(cin, message);

3. transmitMsg(head, cityReceiver, message);
}
break;
case 4:
{
string newCityName;
string prevCityName;
cout << "Enter a new city name: " << endl;
getline(cin, newCityName);
cout << "Enter the previous city name (or First): " << endl;
getline(cin, prevCityName);
// find the node containing prevCity
city *tmp = NULL;
if(prevCityName !="First")
tmp = searchNetwork(head, prevCityName);
// add the new node
head = addCity(head, tmp, newCityName);
printPath(head);
}
break;
case 5: // delete city
{
string city;
cout << "Enter a city name: " << endl;
getline(cin, city);
head = deleteCity(head, city);
printPath(head);
}
break;
case 6: // delete network
head = deleteEntireNetwork(head);
break;
case 7: // quit
quit = true;
cout << "Quitting... cleaning up path: " << endl;
break;

4. default: // invalid input
cout << "Invalid Input" << endl;
break;
}
}
return head;
}
/*
* Purpose: Add a new city to the network
* between the city *previous and the city that follows it in the network.
*/
city* addCity(city *head, city *previous, string cityName )
{
city* add = new city; //to distinguish and create the new node, i named it add
add->name = cityName;
city* tmp = new city;
tmp=head;
if(previous == NULL){
add->next = head;
head = add;
}
while(tmp != NULL && previous != tmp){
tmp = tmp->next;
}
if(tmp == NULL){
if(head == NULL){ // if the head is null then it creates a node for the head
head = add;
add->next = NULL;
}
return head;
}
else{
add->next = tmp->next; //the pointer for the new node will be the next of the prev node
tmp->next = add; // the prev node will now point to the new node
}

5. return head;
}
/*
* Purpose: Search the network for the specified city and return a pointer to that node
*/
city *searchNetwork(city *ptr, string cityName)
{
city *tmp = new city;
tmp = ptr;
while(tmp != NULL && tmp->name != cityName){
tmp = tmp->next;
}
return tmp;
}
/*
* Purpose: deletes all cities in the network starting at the head city.
*/
city* deleteEntireNetwork(city *ptr)
{
city *tmp = new city;
while(ptr->next != NULL){
tmp = ptr->next;
cout << "deleting: " << ptr->name << endl;
delete ptr;
ptr = tmp;
} //stops at the last node, so we need to delete it and make ptr = null
cout << "deleting: " << ptr->name << endl;
delete ptr;
cout << "Deleted network" << endl;
// return head, which should be NULL
return ptr;
}
/* sends messages from file */
void transmitMsg(city *head, string receiver, string message)
{

6. city *sender = new city;
sender = head;
if(head == NULL)
{
cout << "Empty list" << endl;
return;
}
else{
while(sender != NULL && sender->name != receiver){
sender->numberMessages = sender->numberMessages + 1; //adds to the amount of times
the city has intercepted a message
sender->message = message; //the message will be changed everytime for every city
cout << sender->name << " [# messages passed: " << sender->numberMessages <<
"] received: " << sender->message << endl;
sender = sender->next; // moves on to the next city
} // when the destination city is found the same 3 lines of code above will run but will end in
termination of the function
sender->numberMessages = sender->numberMessages +1;
sender->message = message;
cout << sender->name << " [# messages passed: " << sender->numberMessages << "]
received: " << sender->message << endl;
}
}
/*
* Purpose: delete the city in the network with the specified name.
*/
city* deleteCity(city *head, string cityName)
{
city *tmp = new city; //will traverse the list
city *prev = new city; // will hold the previous city for tmp
tmp = head;
if(cityName == head->name){
tmp = head->next;
delete head;
head = tmp;

7. return head;
}
while(tmp != NULL && tmp->name != cityName){
prev = tmp;
tmp = tmp->next;
}
if(tmp == NULL){
cout << "City does not exist." << endl;
}
else{
prev->next = tmp->next; //changes the previous next pointer to skip the deleted node
delete tmp;
}
return head;
}
/*
* Purpose: prints the current list nicely
*/
void printPath(city *ptr)
{
cout << "== CURRENT PATH ==" << endl;
if (ptr == NULL){
cout << "nothing in path" << endl;
}
else{
city *tmp = new city; //to traverse the linked list
tmp = ptr;
while(tmp !=NULL){ //ends the traversal at the end of the list
cout << tmp->name << " -> ";
tmp = tmp->next;
}
cout << "NULL"<next;
addCity(head,tmp,"Denver");
tmp = tmp->next;

8. addCity(head,tmp,"Dallas");
tmp = tmp->next;
addCity(head,tmp,"Atlanta");
tmp = tmp->next;
addCity(head,tmp,"New York");
return head;
}
/*
* Purpose; displays a menu with options
*/
void displayMenu()
{
cout << "Select a numerical option:" << endl;
cout << "======Main Menu=====" << endl;
cout << "1. Build Network" << endl;
cout << "2. Print Network Path" << endl;
cout << "3. Transmit Message" << endl;
cout << "4. Add City" << endl;
cout << "5. Delete City" << endl;
cout << "6. Clear Network" << endl;
cout << "7. Quit" << endl;
}
Solution
#include
#include
#include
#include
using namespace std;
struct city
{
string name; // name of the city
city *next; // pointer to the next city
int numberMessages; // how many messages passed through this city

9. string message; // message we are sending accross
};
city* addCity(city *head, city *previous, string cityName );
city* deleteCity(city *head, string cityName);
city* deleteEntireNetwork(city *head);
city* searchNetwork(city *head, string cityName);
city* loadDefaultSetup(city *head);
void transmitMsg(city *head, string receiver, string filename);
void printPath(city *head);
void displayMenu();
city* handleUserInput(city *head);
/* Do NOT modify main function */
int main(int argc, char* argv[])
{
// pointer to the head of our network of cities
city *head = NULL;
head = handleUserInput(head);
printPath(head);
head = deleteEntireNetwork(head);
if (head == NULL)
cout << "Path cleaned" << endl;
else
printPath(head);
cout << "Goodbye!" << endl;
return 0;
}
/*
* Purpose: handle the interaction with the user
* Do NOT modify
*/
city* handleUserInput(city *head)
{
bool quit = false;
string s_input;
int input;
// loop until the user quits

10. while (!quit)
{
displayMenu();
// read in input, assuming a number comes in
getline(cin, s_input);
input = stoi(s_input);
switch (input)
{
// print all nodes
case 1: //rebuild network
head = loadDefaultSetup(head);
printPath(head);
break;
case 2: // print path
printPath(head);
break;
case 3: //message is read in from file
{
string cityReceiver;
cout << "Enter name of the city to receive the message: " << endl;
getline(cin, cityReceiver);
cout << "Enter the message to send: " << endl;
string message;
getline(cin, message);
transmitMsg(head, cityReceiver, message);
}
break;
case 4:
{
string newCityName;
string prevCityName;
cout << "Enter a new city name: " << endl;
getline(cin, newCityName);
cout << "Enter the previous city name (or First): " << endl;
getline(cin, prevCityName);
// find the node containing prevCity

11. city *tmp = NULL;
if(prevCityName !="First")
tmp = searchNetwork(head, prevCityName);
// add the new node
head = addCity(head, tmp, newCityName);
printPath(head);
}
break;
case 5: // delete city
{
string city;
cout << "Enter a city name: " << endl;
getline(cin, city);
head = deleteCity(head, city);
printPath(head);
}
break;
case 6: // delete network
head = deleteEntireNetwork(head);
break;
case 7: // quit
quit = true;
cout << "Quitting... cleaning up path: " << endl;
break;
default: // invalid input
cout << "Invalid Input" << endl;
break;
}
}
return head;
}
/*
* Purpose: Add a new city to the network
* between the city *previous and the city that follows it in the network.
*/
city* addCity(city *head, city *previous, string cityName )

12. {
city* add = new city; //to distinguish and create the new node, i named it add
add->name = cityName;
city* tmp = new city;
tmp=head;
if(previous == NULL){
add->next = head;
head = add;
}
while(tmp != NULL && previous != tmp){
tmp = tmp->next;
}
if(tmp == NULL){
if(head == NULL){ // if the head is null then it creates a node for the head
head = add;
add->next = NULL;
}
return head;
}
else{
add->next = tmp->next; //the pointer for the new node will be the next of the prev node
tmp->next = add; // the prev node will now point to the new node
}
return head;
}
/*
* Purpose: Search the network for the specified city and return a pointer to that node
*/
city *searchNetwork(city *ptr, string cityName)
{
city *tmp = new city;
tmp = ptr;
while(tmp != NULL && tmp->name != cityName){
tmp = tmp->next;

13. }
return tmp;
}
/*
* Purpose: deletes all cities in the network starting at the head city.
*/
city* deleteEntireNetwork(city *ptr)
{
city *tmp = new city;
while(ptr->next != NULL){
tmp = ptr->next;
cout << "deleting: " << ptr->name << endl;
delete ptr;
ptr = tmp;
} //stops at the last node, so we need to delete it and make ptr = null
cout << "deleting: " << ptr->name << endl;
delete ptr;
cout << "Deleted network" << endl;
// return head, which should be NULL
return ptr;
}
/* sends messages from file */
void transmitMsg(city *head, string receiver, string message)
{
city *sender = new city;
sender = head;
if(head == NULL)
{
cout << "Empty list" << endl;
return;
}
else{
while(sender != NULL && sender->name != receiver){
sender->numberMessages = sender->numberMessages + 1; //adds to the amount of times
the city has intercepted a message
sender->message = message; //the message will be changed everytime for every city

14. cout << sender->name << " [# messages passed: " << sender->numberMessages <<
"] received: " << sender->message << endl;
sender = sender->next; // moves on to the next city
} // when the destination city is found the same 3 lines of code above will run but will end in
termination of the function
sender->numberMessages = sender->numberMessages +1;
sender->message = message;
cout << sender->name << " [# messages passed: " << sender->numberMessages << "]
received: " << sender->message << endl;
}
}
/*
* Purpose: delete the city in the network with the specified name.
*/
city* deleteCity(city *head, string cityName)
{
city *tmp = new city; //will traverse the list
city *prev = new city; // will hold the previous city for tmp
tmp = head;
if(cityName == head->name){
tmp = head->next;
delete head;
head = tmp;
return head;
}
while(tmp != NULL && tmp->name != cityName){
prev = tmp;
tmp = tmp->next;
}
if(tmp == NULL){
cout << "City does not exist." << endl;
}
else{
prev->next = tmp->next; //changes the previous next pointer to skip the deleted node
delete tmp;

15. }
return head;
}
/*
* Purpose: prints the current list nicely
*/
void printPath(city *ptr)
{
cout << "== CURRENT PATH ==" << endl;
if (ptr == NULL){
cout << "nothing in path" << endl;
}
else{
city *tmp = new city; //to traverse the linked list
tmp = ptr;
while(tmp !=NULL){ //ends the traversal at the end of the list
cout << tmp->name << " -> ";
tmp = tmp->next;
}
cout << "NULL"<next;
addCity(head,tmp,"Denver");
tmp = tmp->next;
addCity(head,tmp,"Dallas");
tmp = tmp->next;
addCity(head,tmp,"Atlanta");
tmp = tmp->next;
addCity(head,tmp,"New York");
return head;
}
/*
* Purpose; displays a menu with options
*/
void displayMenu()
{

16. cout << "Select a numerical option:" << endl;
cout << "======Main Menu=====" << endl;
cout << "1. Build Network" << endl;
cout << "2. Print Network Path" << endl;
cout << "3. Transmit Message" << endl;
cout << "4. Add City" << endl;
cout << "5. Delete City" << endl;
cout << "6. Clear Network" << endl;
cout << "7. Quit" << endl;
}