Function with Array Structure

Hi, how you all doing? I currently enroll C++ programming class in some community college, this is my second C++ class. I still have many thing to learn about it.

I am now facing with some class assignment problem that I couldn't go any further, would you guys please help me out here?

It gives me some ERRORs:
-expected constant expression
-cannot allocate an array of constant size 0
-'emp' : unknown size

Here is my program:

Code:

---

#include <iostream>
#include <cstring>
#include <iomanip>
using namespace std;

//STRUCTURE AND UNION//////////////////////////////////////////////////////////////////////

union payRate
{
        long salary;
        float hour;
        int commission;
};

struct Employee
{
        char ID[4];
        char name[36];
        char payStatus[20];
        float grossPay;
};
////////////////////////////////////////////////////////////////////////////////////////////
//FUNCTIONS/////////////////////////////////////////////////////////////////////////////////

int getEmployeeData(Employee*, int);
////////////////////////////////////////////////////////////////////////////////////////////


//MAIN (STARTING POINT)/////////////////////////////////////////////////////////////////////

int main()
{       

        int numEmployee;
        Employee emp[numEmployee];
       

        cout<<"Enter maximum number of employees to enter: ";
        cin>>numEmployee;

        getEmployeeData(emp, numEmployee);

        return 0;
}
////////////////////////////////////////////////////////////////////////////////////////////

//ALL THE FUNCTION DEFINITIONS//////////////////////////////////////////////////////////////

int getEmployeeData(Employee* e, int numEmployee2)
{
        for(int loop=0; loop<numEmployee2; e++)
        {
                cout<<"Enter employee id (Enter to quit): ";
                cin.ignore();
                cin.getline(e->ID,4);

                cout<<"Enter name (Last, First): ";
                cin.ignore();
                cin.getline(e->name,36);

                cout<<"Enter payroll status: ";
                cin.ignore();
                cin.getline(e->payStatus,20);       
       
        }

        return 0;

}

---

Thank you very much
JJ

I think I have to use "Dynamic Memory Allocation" to work with "Array Structure", but I don't really know how to put them together.

Can someones please help me?
JJ

int numEmployee;
Employee emp[numEmployee];


You can't tell the compiler to make an array of an undefined size. Here you declare an integer, but it has not been initialized. Then you attempt to use this value to supposedly make an array of X numbers of employees. Will not work.

2 ways to correct this:

1. Initialize the numEmployee variable with a value within the code or have the value input from the user or a file.

2. This is the best way. Learn about dyamic memory allocation, aka using the heap, and how to use pointers.

First of all thank you very much for your reply.

Quote:

---

Originally Posted by MacNilly

1. Initialize the numEmployee variable with a value within the code or have the value input from the user or a file.

---

-Do you mean I have to initialize the "numEmployee" variable within Function? But then "Employee emp" will not become an "Array".

Quote:

---

Originally Posted by MacNilly

2. This is the best way. Learn about dyamic memory allocation, aka using the heap, and how to use pointers.

---

-I am trying to use "Dynamic Memory Allowcation" but it doesn't work and it gave me like 104 errors!!! I really don't understand how to put DMA to work with Function Array.

Would you please give me some example of using DMA with Functin Array?

I appriciate very much
JJ

All I'm saying is that you can't make an array of an undefined size. In your code, you have to have the user input the number of employees (numEmployee) BEFORE you attempt to create an array of numEmployee size.

As far as using the heap, there are tutorials on here. Look for the "new" keyword.

Static array

Code:

---

const int numEmployee = 5;
Employee emp[numEmployee];

---

Dynamic array

Code:

---

int numEmployee;
Employee *emp;

cout<<"Enter maximum number of employees to enter: ";
cin>>numEmployee;

emp = new Employee[numEmployee];
// do all kind of stuff

// when you're done, do the following
delete [] emp;

---

I hope I got it right; been awhile coding in c++.

^^ Thank you very much alphaoide and MacNilly^^
JJ :)