This is for C Programming: Please also explain the code in main.c: Thank you. Th

Question

This is for C Programming: Please also explain the code in main.c: Thank you.

The following program allows a user to add to and list entries from a vector ADT, which maintains a list of employees.

Run the program, and provide input to add three employees' names and related data. Then use the list option to display the list.

Modify the program to implement the deleteEntry function.

Run the program again and add, list, delete, and list again various entries.

main.c:

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include "vector_employee.h"

// Add an employee
void AddEmployee(vector *employees) {
Employee theEmployee;

printf(" Enter the name to add: ");
fgets(theEmployee.name, 50, stdin);
theEmployee.name[strlen(theEmployee.name) - 1] = ''; // Remove trailing newline

printf("Enter %s's department: ", theEmployee.name);
fgets(theEmployee.department, 50, stdin);
theEmployee.department[strlen(theEmployee.department) - 1] = ''; // Remove trailing newline

printf("Enter %s's title: ", theEmployee.name);
fgets(theEmployee.title, 50, stdin);
theEmployee.title[strlen(theEmployee.title) - 1] = ''; // Remove trailing newline

vector_push_back(employees, theEmployee);

printf("%s's information has been added. ", theEmployee.name);

return;
}

// Delete an employee
void DeleteEmployee(vector *employees) {
printf("FIXME: Delete employee ");
// FIXME: Ask the user for the employee # to delete, then delete that employee

return;
}

// List all employees
void ListEmployees(vector *employees) {
int nElements = 0;
int i = 0;

nElements = vector_size(employees);
if (nElements > 0) {
printf(" ");
for (i = 0; i < nElements; ++i) {
printf("%d) Name: %s", i, (*vector_at(employees, i)).name);
printf(", Department: %s", (*vector_at(employees, i)).department);
printf(", Title: %s ", (*vector_at(employees, i)).title);
}
}
else {
printf(" There are no employees to list. ");
}

return;
}

// Get the action the user wants to perform
char GetAction(const char* prompt) {
char answer[50] = "";
char firstChar = '?';

printf(" %s ", prompt);
fgets(answer, 50, stdin);
while (strlen(answer) == 1) {
fgets(answer, 50, stdin);
}
firstChar = toupper(answer[0]);

return firstChar;
}

int main(void) {
const char EXIT_CODE = 'X';
const char PROMPT_ACTION[50] = "Add, Delete, List or eXit (a,d,l,x): ";
vector employees;

vector_create(&employees, 0); // Create empty vector for employees
char userAction = '?';

// Loop until the user enters the exit code.
userAction = GetAction(PROMPT_ACTION);

while (userAction != EXIT_CODE) {
switch (userAction) {
case 'A': AddEmployee(&employees);
break;
case 'D': DeleteEmployee(&employees);
break;
case 'L': ListEmployees(&employees);
break;
default : // Do nothing
break;
}
  
userAction = GetAction(PROMPT_ACTION);
}

return 0;
}

vector_employee.h:

#ifndef VECTOREMPLOYEE_H
#define VECTOREMPLOYEE_H

// struct and typedef for Employee
typedef struct EmployeeStruct {
char name[50];
char department[50];
char title[50];
} Employee;

// struct and typedef declaration for Vector ADT
typedef struct vector_struct {
Employee* elements;
unsigned int size;
} vector;

// interface for accessing Vector ADT

// Initialize vector
void vector_create(vector* v, unsigned int vectorSize);

// Destroy vector
void vector_destroy(vector* v);

// Resize the size of the vector
void vector_resize(vector* v, unsigned int vectorSize);

// Return pointer to element at specified index
Employee* vector_at(vector* v, unsigned int index);

// Insert new value at specified index
void vector_insert(vector* v, unsigned int index, Employee value);

// Insert new value at end of vector
void vector_push_back(vector* v, Employee value);

// Erase (remove) value at specified index
void vector_erase(vector* v, unsigned int index);

// Return number of elements within vector
int vector_size(vector* v);

#endif

vecrot_employee.c:

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

// Initialize vector with specified size
void vector_create(vector* v, unsigned int vectorSize) {
int i = 0;

if (v == NULL) return;

v->elements = (Employee*)malloc(vectorSize * sizeof(Employee));
v->size = vectorSize;
for (i = 0; i < v->size; ++i) {
strcpy(v->elements[i].name, "");
strcpy(v->elements[i].department, "");
strcpy(v->elements[i].title, "");
}
}

// Destroy vector
void vector_destroy(vector* v) {
if (v == NULL) return;

free(v->elements);
v->elements = NULL;
v->size = 0;
}

// Resize the size of the vector
void vector_resize(vector* v, unsigned int vectorSize) {
int oldSize = 0;
int i = 0;
if (v == NULL) return;

oldSize = v->size;
v->elements = (Employee*)realloc(v->elements, vectorSize * sizeof(Employee));
v->size = vectorSize;
for (i = oldSize; i < v->size; ++i) {
strcpy(v->elements[i].name, "");
strcpy(v->elements[i].department, "");
strcpy(v->elements[i].title, "");
}
}

// Return pointer to element at specified index
Employee* vector_at(vector* v, unsigned int index) {
if (v == NULL || index >= v->size) return NULL;

return &(v->elements[index]);
}

// Insert new value at specified index
void vector_insert(vector* v, unsigned int index, Employee value) {
int i = 0;

if (v == NULL || index > v->size) return;

vector_resize(v, v->size + 1);
for (i = v->size - 1; i > index; --i) {
v->elements[i] = v->elements[i-1];
}

strcpy(v->elements[i].name, value.name);
strcpy(v->elements[i].department, value.department);
strcpy(v->elements[i].title, value.title);
}

// Insert new value at end of vector
void vector_push_back(vector* v, Employee value) {
vector_insert(v, v->size, value);
}

// Erase (remove) value at specified index
void vector_erase(vector* v, unsigned int index) {
int i = 0;

if (v == NULL || index >= v->size) return;

for (i = index; i < v->size - 1; ++i) {
v->elements[i] = v->elements[i+1];
}
vector_resize(v, v->size - 1);
}

// Return number of elements within vector
int vector_size(vector* v) {
if (v == NULL) return -1;

return v->size;
}

Explanation / Answer

// Delete an employee

void DeleteEmployee(vector *employees) {

int record;

int nElements = 0;

int i = 0;

printf(" Enter the record number to delete ");

scanf("%d", &record);

nElements = vector_size(employees);

if (nElements > 0) {

for (i = 0; i < nElements; ++i) {

if(i==record) {

employees.erase(employees.begin()+(record-1));

}

}

printf(" Record deleted ");

}

return;

}

Explanation of Main.c

1)Add function :

(a) We create an object of Employee named theEmployee
(b) We ask the user to imput the values for employee name, designation and title one by one and insert the values in the vector using vector_push_back function

2) Delete function :

(a) We ask the user to enter the record number he wishes to delete
(b) Using a local variable to store user input, we cycle through the vector values till the user input matches the vector index of the record we are trying to delete
(c)Using the erase function, we delete the required record

3) List function :

(a) We check if the elements in the vector is greater than 0 and if yes, we iterate through the elements using a for loop and display the employee details associated with each vector index

4) GetAction function :

(a) Here, we use the character entered by user according to the action he wants to perform. If the length of the user input is 1, we convert it to uppercase

5) Main() function :

(a) We ask user to input the specific character according to the action he wants to perform among add employee, delete employee, list all employees or exit
(b) We loop this process until user enters "x" to exit
(c) Using switch, we call the respective functions according to the input of the user

----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.