Question

The project I have is a link list that asks for a name and phone number and it allows the user to insert ,delete ,modify ,and find an element in the structure. The program has a menu in which the user can choose which function they want to use I need to use  switch case to do this but it has not worked I need help with this. Thank you!

#include <iostream>
#include <string>
#include <iomanip>

using namespace std;

const int maxrecs = 5;

//struct definition
struct Teletype
{
string name;
string phoneNo;
Teletype *nextaddr;
};

//function prototype
void display(Teletype *);
void populate(Teletype *);
void modify(Teletype *head, string name);
void insertAtMid(Teletype *, string, string);
void deleteAtMid(Teletype *, string );
int find(Teletype *, string);
bool is_phone_no(string);

//main function
int main()
{

Teletype *list, *current;

string name;
string phoneNo;
int menu;
  
//link nodes
list = new Teletype;//new reserves space and returns the adress to the list
current = list;
  
for(int i=0; i<maxrecs -1; i++)
{
populate(current);
current->nextaddr = new Teletype;
current = current->nextaddr;
}
populate(current);
current->nextaddr=NULL;
cout<< "The contents of the linked list is: "<<endl;
display(list);
  
cout<< "\nPlease select a number from the menu: " << endl;
cout<<"(1)Insert new Structure on the linked list."<< endl;
cout<<"(2)Modify an existing structure in the Linked list."<< endl;
cout<<"(3)Delete an existing structure in the Linked list."<< endl;
cout<<"(4)Find an existing Structure from the Linked list."<< endl;
cout<<"(5)Exit the program."<< endl;

cin>>menu;

switch(menu)
{
case '1':cout<< "Enter Name and number"<< endl;
cin>> name>>phoneNo;
insertAtMid(list, name , phoneNo);
cout<< "The contents of the link list after inserting: "<< endl;
display(list);
break;
case'2': cout << "\nName of the person you need to modify: ";
cin >> name;
modify(list, name);
display(list);
break;
case'3':cout<< endl;
cout<< "Enter Name "<< endl;
cin>> name;
deleteAtMid(list, name);
cout<< endl;
cout<< "The contents of the linked list after deleting John is: "<<endl;
display(list);
break;
case'4':cout<< endl<<endl;
cout<<"Enter a name (last, first): ";
getline(cin, name);// getline because of the namespace
if(!find(list, name))
{
cout<< "The name is not in the current phone list" << endl;
}
break;
case'5':break;
}
return 0;
}

void insertAtMid(Teletype *head, string name, string phone)
{
Teletype *tmp = new Teletype(),*temp2;
tmp->name = name;
tmp->phoneNo = phone;
tmp->nextaddr = head->nextaddr;
temp2=head->nextaddr;
head->nextaddr = tmp;
tmp->nextaddr=temp2;
}

void deleteAtMid(Teletype *head, string name)
{

while(head->nextaddr != NULL)
{
if(head->nextaddr->name == name)
{
Teletype *del = head->nextaddr;
head->nextaddr = head->nextaddr->nextaddr;
delete del;
break;
}
head = head->nextaddr;
}
}
//implementaion
void display(Teletype *contents)
{
while(contents !=NULL)
{
cout<<endl<<setw(30)<< contents->name << setw(20) << contents-> phoneNo;
contents=contents->nextaddr; //get next addr
}
}

int find(Teletype *contents, string name)
{
int found = 0;
  
while(contents != NULL)
{
  
if(contents->name == name)
{
found = 1;
cout<< setw(30) <<contents->name <<setw(20)<<contents->phoneNo;
break; //stop the iterations
}
else
{
contents = contents-> nextaddr;
}
}
cout<< endl;
  
return found;
}

bool is_phone_no(string phoneNo)
{
for (auto it = phoneNo.begin(); it != phoneNo.end(); it++)
{
if (*it > '9' || *it < '0')
return false;
}
return true;
}

void populate(Teletype *record)
{
cout<<"Enter a name: ";
getline(cin,record->name);
string phoneNo;
while (true)
{
  
cout << "Enter the phone number: ";
getline(cin, phoneNo);
try
{
if (!is_phone_no(phoneNo))
{
throw "Exception caught! Invalid phone number\n";
}
record->phoneNo = phoneNo;
break;
}
catch (const char *e)
{
cout << e;
}

}
return;
}

Answer 1

//do comment if any problem arises

//modified code has been highlighted

//you have not implemented modify so commented it

#include <iostream>

#include <string>

#include <iomanip>

using namespace std;

const int maxrecs = 5;

//struct definition

struct Teletype

{

string name;

string phoneNo;

Teletype *nextaddr;

};

//function prototype

void display(Teletype *);

void populate(Teletype *);

// void modify(Teletype *head, string name);

void insertAtMid(Teletype *, string, string);

void deleteAtMid(Teletype *, string);

int find(Teletype *, string);

bool is_phone_no(string);

//main function

int main()

{

Teletype *list, *current;

string name;

string phoneNo;

int menu;

//link nodes

list = new Teletype; //new reserves space and returns the adress to the list

current = list;

for (int i = 0; i < maxrecs - 1; i++)

{

populate(current);

current->nextaddr = new Teletype;

current = current->nextaddr;

}

populate(current);

current->nextaddr = NULL;

cout << "The contents of the linked list is: " << endl;

display(list);

cout << "\nPlease select a number from the menu: " << endl;

cout << "(1)Insert new Structure on the linked list." << endl;

cout << "(2)Modify an existing structure in the Linked list." << endl;

cout << "(3)Delete an existing structure in the Linked list." << endl;

cout << "(4)Find an existing Structure from the Linked list." << endl;

cout << "(5)Exit the program." << endl;

cin >> menu;

switch (menu)

{

case 1:

cout << "Enter Name and number" << endl;

cin >> name >> phoneNo;

insertAtMid(list, name, phoneNo);

cout << "The contents of the link list after inserting: " << endl;

display(list);

break;

case 2:

cout << "\nName of the person you need to modify: ";

cin >> name;

// modify(list, name);

display(list);

break;

case 3:

cout << endl;

cout << "Enter Name " << endl;

cin >> name;

deleteAtMid(list, name);

cout << endl;

cout << "The contents of the linked list after deleting John is: " << endl;

display(list);

break;

case 4:

cout << endl

<< endl;

cout << "Enter a name (last, first): ";

getline(cin, name); // getline because of the namespace

if (!find(list, name))

{

cout << "The name is not in the current phone list" << endl;

}

break;

case 5:

break;

}

return 0;

}

void insertAtMid(Teletype *head, string name, string phone)

{

Teletype *tmp = new Teletype(), *temp2;

tmp->name = name;

tmp->phoneNo = phone;

tmp->nextaddr = head->nextaddr;

temp2 = head->nextaddr;

head->nextaddr = tmp;

tmp->nextaddr = temp2;

}

void deleteAtMid(Teletype *head, string name)

{

while (head->nextaddr != NULL)

{

if (head->nextaddr->name == name)

{

Teletype *del = head->nextaddr;

head->nextaddr = head->nextaddr->nextaddr;

delete del;

break;

}

head = head->nextaddr;

}

}

//implementaion

void display(Teletype *contents)

{

while (contents != NULL)

{

cout << endl

<< setw(30) << contents->name << setw(20) << contents->phoneNo;

contents = contents->nextaddr; //get next addr

}

}

int find(Teletype *contents, string name)

{

int found = 0;

while (contents != NULL)

{

if (contents->name == name)

{

found = 1;

cout << setw(30) << contents->name << setw(20) << contents->phoneNo;

break; //stop the iterations

}

else

{

contents = contents->nextaddr;

}

}

cout << endl;

return found;

}

bool is_phone_no(string phoneNo)

{

for (auto it = phoneNo.begin(); it != phoneNo.end(); it++)

{

if (*it > '9' || *it < '0')

return false;

}

return true;

}

void populate(Teletype *record)

{

cout << "Enter a name: ";

getline(cin, record->name);

string phoneNo;

while (true)

{

cout << "Enter the phone number: ";

getline(cin, phoneNo);

try

{

if (!is_phone_no(phoneNo))

{

throw "Exception caught! Invalid phone number\n";

}

record->phoneNo = phoneNo;

break;

}

catch (const char *e)

{

cout << e;

}

}

return;

}