Question

// CSE240 Fall 2020 HW 7 & 8
// Write your name here
// Write the compiler used: Visual studio or gcc

// READ BEFORE YOU START:
// You are given a partially completed program that creates a linked list of employee information.
// The global linked list 'list' is a list of employees with each node being struct 'employeeList'.
// 'employeeList' consists of struct 'employee' which has: employee name, room number, and a linked list of 'supervisors'.
// The linked list of supervisors has each node containing simply the name of the supervisor.
// HW7 ignores the 'supervisors' linked list since there is no operation/manipulation to be done on 'supervisors' list in HW7.
// HW8 has operations/manipulations to be done with 'supervisors' list like add a supervisor, display last added supervisor.

// To begin, you should trace through the given code and understand how it works.
// Please read the instructions above each required function and follow the directions carefully.
// If you modify any of the given code, the return types, or the parameters, you risk getting compile error.
// You are not allowed to modify main ().
// You can use string library functions.

// ***** WRITE COMMENTS FOR IMPORANT STEPS OF YOUR CODE. *****
// ***** GIVE MEANINGFUL NAMES TO VARIABLES. *****
// ***** Before implementing any function, see how it is called in executeAction() *****

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#pragma warning(disable: 4996) // for Visual Studio

#define MAX_NAME 30

// global linked list 'list' contains the list of employees
struct employeeList {
   struct employee* employee;
   struct employeeList* next;
} *list = NULL;               // currently empty list

// structure "employee" contains the employee's name, room number and linked list of supervisors
struct employee {
   char name[MAX_NAME];
   unsigned int roomNumber;
   struct supervisor* supervisors;       // linked list 'supervisors' contains names of supervisors
};

// structure 'supervisor' contains supervisor's name
struct supervisor {
   char name[MAX_NAME];
   struct supervisor* next;
};

// forward declaration of functions (already implmented)
void flushStdIn();
void executeAction(char);

// functions that need implementation:
// HW 7
void addEmployee(char* employeeNameInput, unsigned int roomNumInput); // 20 points
void displayEmployeeList(struct employeeList* tempList);   // 15 points
struct employee* searchEmployee(char* employeeNameInput);   // 15 points
//HW 8
void addSupervisor(char* employeeNameInput, char* supervisorNameInput);   // 15 points
void displayEmployeeSupervisorList(struct employeeList* tempList);   // 15 points
void removeEmployee(char* employeeNameInput);           // 20 points

int main()
{
   char selection = 'a';       // initialized to a dummy value
   do
   {
       printf("\nCSE240 HW 7,8\n");
       printf("Please enter your selection:\n");
       printf("HW7:\n");
       printf("\t a: add a new employee to the list\n");
       printf("\t d: display employee list (no supervisors)\n");
       printf("\t b: search for an employee on the list\n");
       printf("\t q: quit\n");
       printf("HW8:\n");
       printf("\t c: add a supervisor of a employee\n");
       printf("\t l: display employees who report to a specific supervisor\n");
       printf("\t r: remove an employee\n");
       printf("\t q: quit\n");

       selection = getchar();
       flushStdIn();
       executeAction(selection);
   } while (selection != 'q');

   return 0;
}

// flush out leftover '\n' characters
void flushStdIn()
{
   char c;
   do c = getchar();
   while (c != '\n' && c != EOF);
}

// Ask for details from user for the given selection and perform that action
// Read the function case by case
void executeAction(char c)
{
   char employeeNameInput[MAX_NAME], supervisorNameInput[MAX_NAME];
   unsigned int roomNumInput;
   struct employee* searchResult = NULL;

   switch (c)
   {
   case 'a':   // add employee
               // input employee details from user
       printf("\nPlease enter employee's name: ");
       fgets(employeeNameInput, sizeof(employeeNameInput), stdin);
       employeeNameInput[strlen(employeeNameInput) - 1] = '\0';   // discard the trailing '\n' char
       printf("Please enter room number: ");
       scanf("%d", &roomNumInput);
       flushStdIn();

       if (searchEmployee(employeeNameInput) == NULL)   // un-comment this line after implementing searchEmployee()                  
       //if (1)                                   // comment out this line after implementing searchEmployee()
       {
           addEmployee(employeeNameInput, roomNumInput);
           printf("\nEmployee successfully added to the list!\n");
       }
       else
           printf("\nThat employee is already on the list!\n");
       break;

   case 'd':       // display the list
       displayEmployeeList(list);
       break;

   case 'b':       // search for an employee on the list
       printf("\nPlease enter employee's name: ");
       fgets(employeeNameInput, sizeof(employeeNameInput), stdin);
       employeeNameInput[strlen(employeeNameInput) - 1] = '\0';   // discard the trailing '\n' char

       if (searchEmployee(employeeNameInput) == NULL)   // un-comment this line after implementing searchEmployee()                  
       //if (0)                                   // comment out this line after implementing searchEmployee()
           printf("\nEmployee name does not exist or the list is empty! \n\n");
       else
       {
           printf("\nEmployee name exists on the list! \n\n");
       }
       break;

   case 'r':       // remove employee
       printf("\nPlease enter employee's name: ");
       fgets(employeeNameInput, sizeof(employeeNameInput), stdin);
       employeeNameInput[strlen(employeeNameInput) - 1] = '\0';   // discard the trailing '\n' char

       if (searchEmployee(employeeNameInput) == NULL)   // un-comment this line after implementing searchEmployee()                  
       //if (0)                                   // comment out this line after implementing searchEmployee()
           printf("\nEmployee name does not exist or the list is empty! \n\n");
       else
       {
           removeEmployee(employeeNameInput);
           printf("\nEmployee successfully removed from the list! \n\n");
       }
       break;

   case 'c':       // add supervisor
       printf("\nPlease enter employee's name: ");
       fgets(employeeNameInput, sizeof(employeeNameInput), stdin);
       employeeNameInput[strlen(employeeNameInput) - 1] = '\0';   // discard the trailing '\n' char

       if (searchEmployee(employeeNameInput) == NULL)   // un-comment this line after implementing searchEmployee()                  
       //if (0)                                       // comment out this line after implementing searchEmployee()
           printf("\nEmployee name does not exist or the list is empty! \n\n");
       else
       {
           printf("\nPlease enter supervisor's name: ");
           fgets(supervisorNameInput, sizeof(supervisorNameInput), stdin);
           supervisorNameInput[strlen(supervisorNameInput) - 1] = '\0';   // discard the trailing '\n' char

           addSupervisor(employeeNameInput, supervisorNameInput);
           printf("\nSupervisor added! \n\n");
       }
       break;

   case 'l':       // list supervisor's employees
       displayEmployeeSupervisorList(list);
       break;

   case 'q':       // quit
       break;

   default: printf("%c is invalid input!\n", c);
   }
}

// HW7 Q1: addEmployee (20 points)
// This function is used to insert a new employee in the linked list.
// You must insert the new employee to the head of linked list 'list'.
// You need NOT check if the employee already exists in the list because that is taken care by searchEmployee() called in executeAction(). Look at how this function is used in executeAction().
// Don't bother to check how to implement searchEmployee() while implementing this function. Simply assume that employee does not exist in the list while implementing this function.
// NOTE: The function needs to add the employee to the head of the list.
// NOTE: This function does not add supervisors to the employee info. There is another function addSupervisor() in HW8 for that.
// Hint: In this question, no supervisors means NULL supervisors.

void addEmployee(char* employeeNameInput, unsigned int roomNumInput)
{
   // YOUR CODE HERE
}

// HW7 Q2: displayEmployeeList (15 points)
// This function displays the employee details (struct elements) of each employee.
// Parse through the linked list 'list' and print the employee details ( name and room number) one after the other. See expected output screenshots in homework question file.
// You should not display supervisor names (because they are not added in HW7).
// You MUST use recursion in the function to get full points. Notice that 'list' is passed to the function argument. Use recursion to keep calling this function till end of list.

void displayEmployeeList(struct employeeList* tempList)
{
   // YOUR CODE HERE

}

// HW7 Q3: searchEmployee (15 points)
// This function searches the 'list' to check if the given employee exists in the list. Search by employee name.
// If it exists then return that 'employee' node of the list. Notice the return type of this function.
// If the employee does not exist in the list, then return NULL.
// NOTE: After implementing this fucntion, go to executeAction() to comment and un-comment the lines mentioned there which use searchEmployee()
// in case 'a', case 'r', case 'l' (total 3 places)
struct employee* searchEmployee(char* employeeNameInput)
{

   struct employeeList* tempList = list;           // work on a copy of 'list'
  
   // YOUR CODE HERE

   return NULL;
}

Help me complete the code thank you.

Answer 1

// I am attaching the code, didn't have time to compile. I'm sure you can follow along and make changes if required

// Do put the effort in understanding the comments.

void addEmployee(char *employeeNameInput, unsigned int roomNumInput)

{

    // YOUR CODE HERE

    // create new employee

    employee* new_employee = malloc(sizeof(employee)); // allot new memory

    strcpy(new_employee->name, employeeNameInput); // copy

    new_employee->roomNumber = roomNumInput; // copy

    

    // add to the 'list'

    employeeList* new_node = malloc(sizeof(employeeList)); // allot new memory for node in the list

    new_node->employee = new_employee; // copy pointer

    if(list != NULL) // if list is not empty

        new_node->next = list->next; // adding before the head

    else

        new_node->next = NULL; // first node in the list (so next node is null)

    list = new_node; // create the new head

}

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void displayEmployeeList(struct employeeList *tempList)

{

    // YOUR CODE HERE

    if(tempList != NULL) // till list doesn't end

    {

        printf("%s\n",*(tempList->employee->name)); // display name

        printf(("%d\n",*(tempList->employee->roomNumber))); // display room number

        displayEmployeeList(tempList->next); // resursively display next node

    }

}

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struct employee *searchEmployee(char *employeeNameInput)

{

    struct employeeList *tempList = list; // work on a copy of 'list'

    // YOUR CODE HERE

    while(tempList != NULL);

    {

        if(strcmp (tempList->employee->name, employeeNameInput) == 0 ) // if employee is found (compare the two strings)

        {

            return tempList->employee; // return employee pointer from the node

        }

        tempList=tempList->next; // go to next node if not found

    }

    return NULL;

}

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