Question

I am having trouble fixing my build errors. The compiler I am using is Visual Studio.Thanks.

#include <iostream>
#include <string>
#include <cstdlib>

using namespace std;

/*
* structure to store employee details
* employee details are stored as linked list
*/
struct Employee
{
private:

   string full_name; //full name
   double net_income; //income

public:
   struct Employee *next; //pointing to the next employee details in the list

                       /*
                       * create new employee node
                       */
   Employee(string full_name, double net_income)
   {
       this->full_name = full_name;
       this->net_income = net_income;
       this->next = NULL;
   }

   /*
   * display the details of this employee
   */
   void displayDetails()
   {
       cout << "\tFull name : " << full_name << endl;
       cout << "\tDaily salary: " << net_income << endl << endl;
   }
};

/*
* Implementation of Queue
*/
class EmployeeQueue
{
   struct Employee *front = NULL, *rear = NULL; // front and rear pointers of queue

public:
   /*
   * inset a new employee details into queue
   * this function take argument as a pointer to employee struct
   */
   void enqueue(struct Employee *newEmployee)
   {
       if (rear == NULL)
       {
           /*
           * empty wueue
           */
           rear = newEmployee;
           front = newEmployee;
       }
       else
       {
           /*
           * not empty
           * inseting new details at rear
           */
           rear->next = newEmployee;
           rear = newEmployee;
       }
   }

   /*
   * remove employee who is in front of the queue
   * this function return a pointer to employee struct
   */
   Employee* dequeue()
   {
       if (front == NULL)
       {
           /*
           * empty queue
           */
           return NULL;
       }

       /*
       * details of employee who is in front
       */
       struct Employee *leavingEmployee = front;

       front = front->next;

       if (front == NULL)
           rear = NULL;

       return leavingEmployee;
   }
};

int main()
{
   Employee * employee; //pointer of employee structure
   EmployeeQueue *queue = new EmployeeQueue(); //pointer of employee queue

   int ch = 0;
   string first_name;
   string last_name;
   string full_name;
   double work_hours;
   double hourly_rate;
   double tax_rate;
   double gross_salary;
   double net_salary;

   /*
   * iterate user inputs until exit command
   */

   while (ch != 3)
   {
       /*
       * displaying main menu
       */
       cout << endl << "1. Enter an employee information" << endl;
       cout << "2. Display information of employee who is leaving the work" << endl;
       cout << "3. Exit program" << endl;
       cout << "Enter your choice: ";
       cin >> ch; //getting choice

               /*
               * processing user choice
               */
   }

   switch (ch)
   {
   case 1:
   {   /*
       * choice to add new employee
       *
       * getting input of employee details
       */
       cout << "\tEnter first name of employee : ";
       cin >> first_name;
       cout << "\tEnter the last name of the employee : ";
       cin >> last_name;
       cout << "\tEnter working hours of the employee : ";
       cin >> work_hours;
       cout << "\tEnter the hourly working rate of the employee: ";
       cin >> hourly_rate;
       cout << "\tEnter the tax rate (%) of the employee : ";
       cin >> tax_rate;

       /*
       * finding full name
       *
       * full name = first name + last name
       */
       full_name = first_name + " " + last_name;

       /*
       * calculating gross salary
       *
       * gross salary = working hours * hourly rate
       */
       gross_salary = (work_hours * hourly_rate);

       /*
       * calculating net salary
       *
       * net salary = gross salary - (gross salary * (tax rate / 100)
       */
       net_salary = gross_salary - (gross_salary * tax_rate / 100.0);

       /*
       * creating new employee structure
       */
       employee = new Employee(full_name, net_salary);

       /*
       * inserting new employee details into queue
       */

       queue->enqueue(employee);
   }
   break;
   {case 2:
       /*
       * choice to display details
       */
       /*
       * getting details of employee who is leaving
       */
       employee = queue->dequeue();
   }
   if (employee != NULL)
   {
       /*
       * if not null displaying details
       */
       cout << "\tDetails of employee who is leaving:" << endl;
       employee->displayDetails();
   }
   else
   {
       /*
       * queue is empty
       */
       cout << "Queue is empty." << endl;
   }
   break;
   {   case 3:
       /*
       * choice to exit
       *
       * free all memories allocated dynamically
       */

   Employee * employee = NULL;
   free(employee);
   free(queue);
   break;
  
   default:
       /*
       * invalid choice
       */
       cout << "Invalid choice. Please enter it again." << endl;
  
   }
   }
   system("pause");
   return 0;

};

Answer 1

//corrected program

#include <iostream>
#include <string>
#include <cstdlib>

using namespace std;

/*
* structure to store employee details
* employee details are stored as linked list
*/
struct Employee
{
private:

string full_name; //full name
double net_income; //income

public:
struct Employee *next; //pointing to the next employee details in the list

/*
* create new employee node
*/
Employee(string full_name, double net_income)
{
this->full_name = full_name;
this->net_income = net_income;
this->next = NULL;
}

/*
* display the details of this employee
*/
void displayDetails()
{
cout << "\tFull name : " << full_name << endl;
cout << "\tDaily salary: " << net_income << endl << endl;
}
};

/*
* Implementation of Queue
*/
class EmployeeQueue
{
struct Employee *front = NULL, *rear = NULL; // front and rear pointers of queue

public:
/*
* inset a new employee details into queue
* this function take argument as a pointer to employee struct
*/
void enqueue(struct Employee *newEmployee)
{
if (rear == NULL)
{
/*
* empty wueue
*/
rear = newEmployee;
front = newEmployee;
}
else
{
/*
* not empty
* inseting new details at rear
*/
rear->next = newEmployee;
rear = newEmployee;
}
}

/*
* remove employee who is in front of the queue
* this function return a pointer to employee struct
*/
Employee* dequeue()
{
if (front == NULL)
{
/*
* empty queue
*/
return NULL;
}

/*
* details of employee who is in front
*/
struct Employee *leavingEmployee = front;

front = front->next;

if (front == NULL)
rear = NULL;

return leavingEmployee;
}
};

int main()
{
Employee * employee; //pointer of employee structure
EmployeeQueue *queue = new EmployeeQueue(); //pointer of employee queue

int ch = 0;
string first_name;
string last_name;
string full_name;
double work_hours;
double hourly_rate;
double tax_rate;
double gross_salary;
double net_salary;

/*
* iterate user inputs until exit command
*/

while (ch != 3)
{
/*
* displaying main menu
*/
cout << endl << "1. Enter an employee information" << endl;
cout << "2. Display information of employee who is leaving the work" << endl;
cout << "3. Exit program" << endl;
cout << "Enter your choice: ";
cin >> ch; //getting choice

/*
* processing user choice
*/

switch (ch)
{
case 1:
{ /*
* choice to add new employee
*
* getting input of employee details
*/
cout << "\tEnter first name of employee : ";
cin >> first_name;
cout << "\tEnter the last name of the employee : ";
cin >> last_name;
cout << "\tEnter working hours of the employee : ";
cin >> work_hours;
cout << "\tEnter the hourly working rate of the employee: ";
cin >> hourly_rate;
cout << "\tEnter the tax rate (%) of the employee : ";
cin >> tax_rate;

/*
* finding full name
*
* full name = first name + last name
*/
full_name = first_name + " " + last_name;

/*
* calculating gross salary
*
* gross salary = working hours * hourly rate
*/
gross_salary = (work_hours * hourly_rate);

/*
* calculating net salary
*
* net salary = gross salary - (gross salary * (tax rate / 100)
*/
net_salary = gross_salary - (gross_salary * tax_rate / 100.0);

/*
* creating new employee structure
*/
employee = new Employee(full_name, net_salary);

/*
* inserting new employee details into queue
*/

queue->enqueue(employee);

break;}
case 2:{

/*
* choice to display details
*/
/*
* getting details of employee who is leaving
*/
employee = queue->dequeue();

if (employee != NULL)
{
/*
* if not null displaying details
*/
cout << "\tDetails of employee who is leaving:" << endl;
employee->displayDetails();
}
else
{
/*
* queue is empty
*/
cout << "Queue is empty." << endl;
}
break;}
case 3:{
  
/*
* choice to exit
*
* free all memories allocated dynamically
*/

Employee * employee = NULL;
free(employee);
free(queue);
break;}
  
default:
/*
* invalid choice
*/
cout << "Invalid choice. Please enter it again." << endl;
  
}
}
system("pause");
return 0;

};

//sample output