Vector Operations in C++ -- Part 3

In the last post, we implemented the searching procedure followed in the Employee Register. Now we will discuss the CRUD operations on the vector with Employee class.

To go to the previous two posts,
Vector Operations in C++ -- Part 1 and
Vector Operations in C++ -- Part 2

For adding an employee, we need to first check if another employee of the same employee ID exists in the vector. If it exists, we should give the relevant message to the user. Since we know that adding or deleting the employees at the ends is done very quickly, we have used the function "push_back" to add the new employee to the end.

void EmployeeRegister::addEmployee(Employee emp) { // Add the record to emp_records vector and the ID to emp_id_records emp_records.push_back(emp); emp_id_records.push_back(emp.getId()); cout<<"\n\n\n---------------------------------------------------------"; cout<<"\n Employee successfully added with the following details"; cout<<"\n---------------------------------------------------------"; cout<<"\n Employee ID: \t\t"<<emp.getId(); cout<<"\n Employee Name: \t"<<emp.getName(); cout<<"\n---------------------------------------------------------"; cout<<"\n\n"; }

For displaying the employee details, we must first check if the vector is empty. If it is empty, we need not traverse through the vector.

void EmployeeRegister::displayEmployees() { // First check if the employee vector is empty if(isEmpty()) { cout<<"\n No Employee records to display"; return; } // If the vector has some elements, print them in a tabular format cout<<"\n\n\n\n--------------------------------------------------------------"; cout<<"\n Employee ID \t | \t Employee Name"; cout<<"\n--------------------------------------------------------------"; for(int i=0;i<emp_records.size();i++) { cout<<"\n "<<emp_records[i].getId()<<" \t\t | \t "<<emp_records[i].getName(); } cout<<"\n--------------------------------------------------------------\n\n\n"; }

For deleting and updating an employee details, we need to check if the employee with the given ID exists. If it does not exist, the relevant message must be displayed.

int EmployeeRegister::updateEmployee(int id,Employee emp) { // Before updating, first check whether the employee with the given ID exists or not. // If employee with the given ID does not exist, return -1 if(searchEmployee(id)==-1) return -1; else { // Update the employee details in the index to the newly entered details emp_records[searchEmployee(id)]=emp; cout<<"\n\n\n---------------------------------------------------------"; cout<<"\n Employee successfully updated to the following"; cout<<"\n---------------------------------------------------------"; cout<<"\n Employee ID: \t\t"<<emp.getId(); cout<<"\n Employee Name: \t"<<emp.getName(); cout<<"\n---------------------------------------------------------"; cout<<"\n\n"; return 1; } } int EmployeeRegister::deleteEmployee(int id) { // Before deleting, first check whether the employee with the given ID exists or not. // If employee with the given ID does not exist, return -1 if(searchEmployee(id)==-1) return -1; else { // Delete the record from emp_records vector and the ID from emp_id_records emp_records.erase(emp_records.begin()+searchEmployee(id)); emp_id_records.erase(emp_id_records.begin()+searchEmployee(id)); cout<<"\n Employee with employee ID "<<id<<" is successfully deleted\n\n"; return 1; } }

Till now we have done all the operations required for manipulating or displaying the employee data. But a good user interface which is easily understandable by the user is equally important. Thus, we will have a menu with all the above discussed operations. To take numerical and string input from the user, we use two member functions in the class "EmployeeDisplay". Validation to the complete extent is not done for numerical and string inputs.

Compiling and running the case study:

Compiling:

g++ -o EmployeeRegister main.cpp Display.cpp Employee.cpp EmployeeRegister.cpp

Running the executable:

./EmployeeRegister

Sample Output for an add operation in the following menu is given below.

****************************************************************** ****************WELCOME TO THE EMPLOYEE REGISTER****************** ****************************************************************** 1. Add an employee 2. Delete an employee 3. Display Employees list 4. Update an employee 5. Exit Enter the choice: 1 Enter the Employee ID of the employee to be added: 1 Enter the Employee name of the employee to be added: Sai Ravi Kiran --------------------------------------------------------- Employee successfully added with the following details --------------------------------------------------------- Employee ID: 1 Employee Name: Sai Ravi Kiran ---------------------------------------------------------

I have uploaded the entire project at the following link: Vector Operations Case Study. You can download the "Employee Register.zip" from this link.