Question

You will design a program to keep track of a restaurants waitlist using a queue implemented with a linked list.

1. Create a class named waitList that can store a name and number of guests. Use constructors to automatically initialize the member variables.
2. Add the following operations to your program:
   1. Return the first person in the queue
   2. Return the last person in the queue
   3. Add a person to the queue
   4. Delete a person from the queue
3. Create a main program to test your class. Your main program should contain the following options.
   1. Add a guest (adds the reservation name and number of guests)
   2. Delete a guest (the user must give you the name to delete, the list may be empty or the guest may not be in the list)
   3. Show last guest waiting (return NONE if the queue is empty)
   4. Show first guest waiting (return NONE if the queue is empty)
   5. Exit (Language: C++)

Answer 1

//c++ program for QUEUE using linked list for waitList class

#include<iostream>
#include<stdio.h>
#include<stdlib.h>
#include <string>
#include <string.h>
using namespace std;

//node class definition for data and links
class node
{
public :
string name;
int guestnum;
node *next;

};

//waitList class is implemented various operations

class waitList:public node
{
node *head;
int front,rare;
public :

//constructor taking default data
waitList()
{
front=-1;
rare=-1;
head =new node;
head->next=NULL;
head->name="jklji";
head->guestnum=6;
rare ++;
}

//push method to add data to list

void push(string nm,int x)
{
if (rare < 0 )
{
head =new node;
head->next=NULL;
head->name=nm;
head->guestnum=x;
rare ++;
}
else
{
node *temp,*temp1;
temp=head;
rare++;
while(temp->next != NULL)
temp=temp->next;
temp1=new node;
temp->next=temp1;
temp1->next=NULL;
temp1->name=nm;
temp1->guestnum=x;
} }

//displaying all data in wait list

void display()
{
node *temp;
temp=head;
if (rare < 0)
{
cout <<" queue under flow";
return;
}
while(temp != NULL)
{
cout <<temp->name<< " "<<temp->guestnum<<endl;
temp=temp->next;
}
}

//removing head node using pop method
void pop()
{
node *temp;
temp=head;
if( rare < 0 || front >rare)
{
cout <<"queue under flow";
return;
}
if(front == rare)
{
front = rare =-1;
head=NULL;
return;
}
front++;
head=head->next;
}

//del method for removing node if name equals to any node name.
void del(string nm)
{
node *temp,*temp1;
temp=head;
if( rare < 0)
{
cout <<"queue under flow";
return;
}
if(temp->name==nm)
{
cout<<temp->name<<"data node is deleting"<<endl;
head=temp->next;
rare--;
return;
}
while((temp != NULL))
{
if(temp->name==nm)
{
cout<<temp->name<<"data node is deleting"<<endl;
temp1->next=temp->next;
rare--;
return;
}
temp1=temp;
temp=temp->next;

}

}

//shows first node name
string showfirst()
{
if( rare < 0)
{
cout <<"queue under flow";
return NULL;
}
return head->name;
}

//shows last node name
string showlast()
{

node *temp;
temp=head;
if( rare < 0)
{
cout <<"queue under flow";
return NULL;
}
while(temp->next != NULL)
{
temp=temp->next;
cout<<"nm"<<temp->name;
}

return temp->name;
}
};
int main()
{
string name;
waitList obj;

int numguest;
int ch;
while(1)
{
cout <<"\nQUEUE OPERATIONS :\n1.PUSH\n2.POP\n3.DISPLAY\n4.OTHER OPERATIONS\n enter your choice:\n";
cin >> ch;
switch(ch)
{
case 1:
cout <<"\n enter restaurant name and number of guests :";
cin>>name;
cin>>numguest;
obj.push(name,numguest);
break;

case 2: obj.pop();
break;
case 3: obj.display();
break;
case 4: while(1)
{
cout <<"\nOTHER OPERATIONS :\n1.ADD \n2.DELETE\n3.SHOW FIRST GUEST\n4.SHOW LAST GUEST\n5.DISPLAY\n6.EXIT\n enter your choice:\n";
cin >> ch;
switch(ch)
{
case 1:
cout <<"\n enter restaurant name and number of guests :";
cin>>name;
cin>>numguest;
obj.push(name,numguest);
break;

case 2: cout <<"\n enter name of guest to delete :";
cin>>name;
obj.del(name);
break;
case 3: name=obj.showfirst();
cout<<"first person is:"<<name;
break;
case 4: name=obj.showlast();
cout<<"last person is:"<<name;
break;
case 5: obj.display();
break;
case 6: exit(0);
default: cout<<"Invalid choice.Try again\n";
}
};
default: cout<<"Invalid choice.Try again\n";
}
}

return 0;
}

//output of the screenshot is shown below

X D:\Users\ssssss\Documents\qu.exe QUEUE OPERATIONS: 11.PUSH 2.POP 3.DISPLAY 4.OTHER OPERATIONS enter your choice: 3 jklji 6 QUEUE OPERATIONS: 1.PUSH 2.POP 3.DISPLAY 4.OTHER OPERATIONS enter your choice: 4 OTHER OPERATIONS: 1.ADD 2.DELETE 3.SHOW FIRST GUEST 4.SHOW LAST GUEST 5.DISPLAY 6.EXIT enter your choice: :hi 4 enter restaurant name and number of guests OTHER OPERATIONS : 1.ADD 2.DELETE 3.SHOW FIRST GUEST 4.SHOW LAST GUEST 5.DISPLAY 6.EXIT enter your choice : 11 enter restaurant name and number of guests OTHER OPERATIONS: 1. ADD 2.DELETE 3.SHOW FIRST GUEST 4.SHOW LAST GUEST 5.DISPLAY 6.EXIT enter your choice: jklji 6 hi 4 truo 2 :truo 2 OTHER OPERATIONS : 1. ADD 1