Question

implementing linked list using c++

1. Develop an algorithm to implement an employee list with employee ID, name, designation and department using linked list and perform the following operations on the list.

1. Add employee details based on department
2. Remove employee details based on ID if found, otherwise display appropriate message
3. Display employee details
4. Count the number of employees in each department

Answer 1

I Have Atteched screenshots of output of program

#include<bits/stdc++.h>
using namespace std;
struct  Employee
{
    
    int employeeID;
    string name;
    string  designation;
    string department;
    Employee *next;
    Employee(int EmployeeID,string Name,string Designation,string Department){
        employeeID=EmployeeID;
        name=Name;
        designation=Designation;
        department=Department;
        next=NULL;
    }
};
//It will return the pointer of new employee

Employee  *AddEmployee(unordered_map<string,int>&department_count,unordered_map<int,bool>&cheking_id){
    
    string name,designation,department;
    int employeeID;
    bool br=true;
    while(br){
    cout<<"Enter EmploeeID: ";
    cin>>employeeID;
    
    if(cheking_id[employeeID]==true)
    {
        cout<<"Employee Id is Already Prsent,Please enter Other Id\n";

    }else{
        cheking_id[employeeID]=true;
        br=false;
    }


    }

    cout<<"Enter Name: ";
    cin>>name;
    cout<<"Enter Department: ";
    cin>>department;
    cout<<"Enter designation : ";
    cin>>designation;
    Employee *nw=new Employee(employeeID,name,designation,department);
//It is used to count department type
    department_count[department]++;
    return nw;

}
//deleting the emplyee

Employee*  deleteEmployee(Employee *first, unordered_map<string,int>&department_count,unordered_map<int,bool>&cheking_id){
    int ID;
    cout<<"Enter Employee Id:";
    cin>>ID;
    Employee *temp=first,*prev=NULL;

    //maintaining prev so we could get parent pointer of deleting Node

    while(temp!=NULL&&temp->employeeID!=ID){
        prev=temp;
        temp=temp->next;
    }
//if temp is NULL that means that employeeId is not present
    if(temp!=NULL){
        //we are deleting the employee so we need to delete
        //employee department we counted and employeeid 
        department_count[temp->department]--;
        cheking_id[temp->employeeID]=false;
         //Handling case where deleting node is first node
        if(temp!=first){
        prev->next=temp->next;
        cout<<"Successfully deleted record of Employee "<<temp->name<<endl;
        }else{
            first=first->next;

        }
        delete temp;
        

    }else
    {
        cout<<"Entered ID Employee is not listed in Company\n";

    }
    return first;
    

}


void displayAll(Employee *first){
    Employee *temp=first;
    if(first==NULL)
    {
        cout<<"We Don't have any emploee details\n";
        return;
    }
    while(temp!=NULL){
        cout<<"Employee ID: "<<temp->employeeID<<endl;
        cout<<"Employee name: "<<temp->name<<endl;
        cout<<"Employee Designation: "<<temp->designation<<endl;
        cout<<"Emplyee department : "<<temp->department<<endl;
        temp=temp->next;
        cout<<endl;
    }

}

void displayEmployeeDetails(Employee *first){
     Employee *temp=first;
    if(first==NULL)
    {
        cout<<"We Don't have any emploee details\n";
        return;
    }
    bool found=false;
    int id;
    cout<<"Enter EmployeeID:";
    cin>>id;
    //traversing linked list to get add details of employess
    while(temp!=NULL){

       if(id==temp->employeeID)
       {
           cout<<"===Employee Details===\n";
        cout<<"Employee ID: "<<temp->employeeID<<endl;
        cout<<"Employee name: "<<temp->name<<endl;
        cout<<"Employee Designation: "<<temp->designation<<endl;
        cout<<"Emplyee department : "<<temp->department<<endl;
         
           cout<<endl;
        found=true;
        break;
       }
        temp=temp->next;
    }
    if(!found)
    cout<<"Entered EmployeeID Employee is not found\n";

}


void displayDepartmentCount(unordered_map<string,int>&department_count){
       if(department_count.size()==0)
       {
           cout<<"NO Emploee Details Present\n";
           return;
       }
       //print the department and its count

       for(auto department:department_count){
           cout<<department.first<<":"<<department.second<<endl;
       }
}


int main(){
   // freopen("input.txt","r",stdin);
    int choice=-1;
     unordered_map<string,int>department_count;
     unordered_map<int,bool>cheking_id;
     Employee *first=NULL,*last=NULL;
    
    while(1){
        cout<<"\n1.Add Employee\n2.Delete Emploee\n3.Display All Emploee Details\n4.Display Perticular Employee Detail\n5.Display count of Each department\n6.Exit\nEnter choice:\n";
        cin>>choice;

        switch (choice)
        {
        case 1:{
               
            /* code */
            
            Employee *nw=AddEmployee(department_count,cheking_id);
            if(first==NULL)
            first=last=nw;
            else
            {
                last->next=nw;
                last=nw;
            }
            

            break;
        }
        case 2:
            first=deleteEmployee(first,department_count,cheking_id);
            break;
        case 3:
            displayAll(first);

            break;
        case 4:
             displayEmployeeDetails(first);
            break;
        case 5:
            displayDepartmentCount(department_count);
            break;
        case 6:
           return 0;
           break;

        default:
        cout<<"Enter Valid choice ";
            break;
        }
    }
    
}