having an array as class attribute - c++

Question

sorry i'm new to c++ and i feel a little stupid for asking, but i can't get it to work after hours of googling and i can't find what i'm doing wrong
the task is pretty easy:
i want to have employees that have name, age etc (those work)
and i want these employees to be stored inside an array.
so i have:
class Employee {
public:
Employee(string, string, int, int);
string name;
string firstName;
int birthYear;
int usedVacation;
int getAge();
};
and then the list:
class EmployeeList {
public:
int addEmployee(string, string, int, int);
Employee eList[500];
};
what i want is: an object that holds an array of Employees, with methods to add/edit etc them.
so i define the addEmployee method outside the class as follows:
int EmployeeList::addEmployee(string first, string last, int year, int used) {
int i = 0;
for (i; i < this.eList.length; i++) {
if (this.eList[i].deleted == true) {
this.eList[i] = {
firstName: first,
lastName : last,
birthYear : year,
usedVacation : used,
deleted : false };
} else {
this.eList.push({ firstName: first, lastName : last, birthYear : year, usedVacation : used, deleted : false });
}
return i;
}
};
As you probably instantly see, there's a lot wrong with that.
All of the this throw Expression must have class type in VS2015,
also identifier firstName is undefined and identifier lastName is undefined,
but in my eyes, there's nothing wrong with my code.
i'm pretty sure this is a very basic thing i just didn't get yet, but i just can't find out, where the problem is.
I defined methods outside Employee, and this works there without a problem (although with this->, but i tried that and it doesn't work either)
please forgive my lack of skills, i come from javascript :(

Answer 1

this.eList[i] =
this is a pointer, not a reference, so you access the members via this->eList. But 99.99% of the time, it's completely unnecessary. You're inside a member method, so the compiler knows what this is. All you need is eList[i] =.
this.eList.push({
First a brief tutorial with arrays in C++. Employee eList[500] doesn't make an array that can hold 500 Employees, eList is 500 Employees. Forever and always. They are are instantly constructed with the default constructor (or will be once you give Employee a default constructor. This is required if you want to have objects in an array, except in very advanced cases).
this.eList.length
There are three actions you can do with arrays: you can access an element with the [i] syntax, they magically convert to a pointer to the first item very often, and finally, if and only if they're a member of a struct, they can be copied. That's all you can do with them. There is no push, because as I said, it is 500 Employee. There is no length member. Yours is always 500 Employees.
if (this.eList[i].deleted == true)
You gave each Employee 4 members, deleted was not one of them. Instead of keeping track of which Employee objects are unused, the normal thing is to keep all the employees in the first few slots, and give EmployeeList a count to keep track of how many "live" employees there are. The live ones are in indecies 0-count. The employees at count-500 are "deleted". Unfortunately, this does mean that when one is deleted, you have to shift forward all the ones after that.
this.eList[i] = {
firstName: first,
lastName : last,
Employee does not have a lastName. The right way to construct an Employee is via the constructor you declared: Employee(string, string, int, int). So that line should probably be eList[i] = Employee(first, last, year, used);. This creates a new Employee object, and then copies it into that slot of the array. Alternatively, just assign the members one by one.

Answer 2

How about something like:
#include<string>
class Employee
{
public:
std::string firstname;
std::lastname;
int birthyear;
int usedVacation;
void setFirstname(std::string fname){firstname = fname;}
void setLastname(std::string lname){lastname = lname;}
void setBirthyear(int year){birthyear = year;}
void setVacation(int vac){usedVacation = vac;}
};
class EmployeeList
{
public:
int count;
EmployeeList eList[500];
EmployeeList()
{
count = 0;
}
void addEmployee(std::string fname, std::string lname, int year, int vac);
void removeEmployee(std::string fname, std::string lname, int year, int vac);
};
void EmployeeList::addEmployee(std::string fname, std::string lname, int year, int vac)
{
//some stuff goes here
count++;
}
void EmployeeList::removeEmployee(std::string fname, std::string lname, int year, int vac)
{
//some stuff goes here
count--;
}
BTW I am not sure where your push, deleted, and length methods came from? You will likely also want to add more methods then what I have written, for example a method to return count. You can also add get methods to the employee class and make your member variables private. I hope this is of some help. Goodluck!