Return an array from a function

[Hypnotik]

Hello everyone. I am writing a program which takes in information to various arrays. I input the info using "set" functions. I then need to output that info from an output function. I'm having problems getting to the information. I think I need to return a pointer to the beginning of the array, although I'm having alot of problems.

 
#include <iostream>
using namespace std;
struct Person
{
    char Fname[20],Lname[20];
    float age;
    int ssn[9],enumber[9];
};
class Employee
{
private:
    int enumber[9],ssn[9];
    float wage;
    char job_title[10];
    Person Per;
public:
    Employee();
    ~Employee(){};
    void SetFname(int emp);
    void SetLname(int emp);
    void Setage();
    void Setssn(int emp);
    void Setenumber(int emp);
    void Setwage();
    void Setjob_title();
    char GetFname();
    char GetLname();
    void Getage();
    int Getssn();
    int Getenumber();
    void Getwage();
    void Getjob_title();
    void output();
    void salary();
    void flipflop();
};
Employee::Employee()
{
    int i=0,j=0;
    cout<<"Constructor."<<endl;
    wage=0;
 
    for (i=0;i<=9;++i)
    {
        enumber[i]=0;
        ssn[i]=0;
    }
 
}
void Employee::SetFname(int emp)
{    
    cout<<"BEGIN SETFNAME FUNCTION."<<endl;
    cout<<"Enter the first name of the employee."<<endl;
    cin.ignore();
    cin.getline (Per.Fname,20,'\n');
    cout<<Per.Fname<<endl;
}
void Employee::SetLname (int emp)
{
    cout<<"BEGIN SETLNAME FUNCTION."<<endl;
    cout<<"Enter the last name of the employee."<<endl;
    cin.getline (Per.Lname,20,'\n');
    cout<<Per.Lname<<endl;
}
void Employee::Setssn(int emp)
{    
    cout<<"SETSSN Function"<<endl;
    cout<<"Enter the social security number of the employee."<<endl;
    cin>>Per.ssn[emp];
    cout<<Per.ssn[emp]<<endl;
 
}
void Employee::Setenumber(int emp)
{
    int i;
    cout<<"SETENUMBER FUNCTION."<<endl;
    cout<<"Enter the employee number."<<endl;
    cin>>Per.enumber[emp];
    cout<<Per.enumber[emp]<<endl;
}
void Employee::output()
{
    int emp;
    cout<<"Which employee's information would you like to view?"<<endl;
    cin>>emp;
    cout<<"Last name:        "<<GetLname()<<endl;
    cout<<"First name:       "<<GetFname()<<endl;
    cout<<"Employee number:  "<<Getenumber()<<endl;
    cout<<"Employee ssn:         "<<Getssn()<<endl;
}
int Employee::Getssn()
{
    cout<<"Getssn function"<<endl;
    return (0);
    //return (Per.ssn[value]);
}
int Employee::Getenumber()
{
    cout<<"Getenumber function"<<endl;
    return(0);
    //return (Per.age);
}
char Employee::GetLname()
{
    cout<<"GetLname function"<<endl;
    return (0);
    //return(Per.Lname);
}
char Employee::GetFname()
{
    cout<<"GetFname function"<<endl;
    return (0);
    //return (Per.Fname);
}
void main()
{
    int emp=-1,choice;
    Employee empl[10];
    while(emp<0||emp>9)
    {
    cout<<"Choose and employee 0-9"<<endl;
    cin>>emp;
    }
    do
    {
    cout<<"Please select what you would like to edit from the menu:"<<endl;
    cout<<"1) Enter the first name."<<endl<<"2) Enter the last name."<<endl<<"3) Enter the social security number."<<endl;
    cout<<"4) Enter the employee number."<<endl<<"5) Enter all of the information."<<endl<<"6) Output the information for employee."<<endl;
    cin>>choice;
        switch(choice)
        {
        case 1:
            empl[emp].SetFname(emp);
            break;
 
        case 2:
            empl[emp].SetLname(emp);
            break;
 
        case 3:
            empl[emp].Setssn(emp);
            break;
 
        case 4:
            empl[emp].Setenumber(emp);
            break;
 
        case 5:
            cout<<"Please enter all of the employees information."<<endl;
            empl[emp].SetFname(emp);
            empl[emp].SetLname(emp);
            empl[emp].Setssn(emp);
            empl[emp].Setenumber(emp);
            break;
 
        case 6:
            cout<<"The employees information is: "<<endl;
            empl[emp].output();
            break;
        }
    }
    while (choice<1||choice>6);
}
 
 

Thanks,
J

[weaknessforcats]

This code:

void Employee::output()
{
int emp;
cout<<"Which employee's information would you like to view?"<<endl;
cin>>emp;
cout<<"Last name: "<<GetLname()<<endl;
cout<<"First name: "<<GetFname()<<endl;
cout<<"Employee number: "<<Getenumber()<<endl;
cout<<"Employee ssn: "<<Getssn()<<endl;
}

is an Employee member function. You have access to Per:

void Employee::output()
{
    int emp;
    cout<<"Which employee's information would you like to view?"<<endl;
    cin>>emp;
    cout<<"Last name:        "<<Per.Lname<<endl;
    cout<<"First name:       "<<Per.Fname()<<endl;
    cout<<"Employee number:  "<<Per.enumber()<<endl;
    cout<<"Employee ssn:         "<<Per.ssn()<<endl;
}
 

Besides your Employee::GetLname() does not return the name. It returns a binary zero. Other get member functions do the same.

This one:

void Employee::SetFname(int emp)
{
cout<<"BEGIN SETFNAME FUNCTION."<<endl;
cout<<"Enter the first name of the employee."<<endl;
cin.ignore();
cin.getline (Per.Fname,20,'\n');
cout<<Per.Fname<<endl;
}

doesn't use the int argment. Why have it?

Also, your functions a loaded with displays and that tells me you are not using your debugger. Learn to use it.

Fix these and then see where you are.

[Hypnotik]

So within my output function I should be accessing the get functions by using (for example) per.getssn()? I have them returning zero because I couldn't get them to return the correct value, and it was my way of troubleshooting to ensure that a value was being returned.

As for the debugger, this is my second c++ class and my instructor has not mentioned using it at all. I plan to ask him in our next meeting about debugger. I attempted to use it...and really didn't understand what was going on with it.

Thanks,

J

[weaknessforcats]

So within my output function I should be accessing the get functions by using (for example) per.getssn()? I have them returning zero because I couldn't get them to return the correct value, and it was my way of troubleshooting to ensure that a value was being returned.

That is correct. Your get functions need to return a copy of the class private data member. This is a little tough when the class data member is an array since you can't return an array from a function.

What you can do is return the array name:

char* Employee::GetFname
{
    return Fname;
}
 

This works because the array name is the address of element 0. Element 0 of the Fname array is a char so the name Fname is the address of a char, that is, a char*.

Unfortunately, this exposes the array to the outside world allowing some hacker-type to use the returned char* to change the contents of the array without needing to use your member functions. Cases like this require returning a constant char* so prevent this from happening.

The correct code would be:

const char* Employee::GetFname
{
    return Fname;
}
 

In your main():

Employee emp;
 
char buffer[80];
cin.getline(buffer,80);    //get the name
emp.SetFname(buffer);  //makes a copy of buffer
cout << emp.GetFname() << endl;
 

I would not put the data entry code inside the member functions.

As for the debugger, this is my second c++ class and my instructor has not mentioned using it at all. I plan to ask him in our next meeting about debugger. I attempted to use it...and really didn't understand what was going on with it.

Don't wait on your instructor. Learn your debugger.

[Hypnotik]

What you can do is return the array name:

char* Employee::GetFname
{
    return Fname;
}
 

This works because the array name is the address of element 0. Element 0 of the Fname array is a char so the name Fname is the address of a char, that is, a char*.

Unfortunately, this exposes the array to the outside world allowing some hacker-type to use the returned char* to change the contents of the array without needing to use your member functions. Cases like this require returning a constant char* so prevent this from happening.

The correct code would be:

const char* Employee::GetFname
{
    return Fname;
}
 

When I do this it gives me the error that Fname is an undeclared identifier. If I return Per.Fname I get a bunch of garbage symbols when I print out the info entered .

J

[phiefer3]

When I do this it gives me the error that Fname is an undeclared identifier.

J

then try this instead:

const char* Employee::GetFname
{
    return &Fname[0];
}
 

that will return the address of the 0 element, and will get around the identifier issue.

Everything else should be the same.

[Hypnotik]

When I use the & I'm receiving the same error. On the other hand &Per.Fname gives me the same garbage output.

[phiefer3]

When I use the & I'm receiving the same error. On the other hand &Per.Fname gives me the same garbage output.

did you do &Fname, or &Fname[0]? because it will make a big difference.

If that doesn't work, then try this, it's a bit much, but:

&(this->Per.Fname[0]);

[Hypnotik]

did you do &Fname, or &Fname[0]? because it will make a big difference.

I tried both, and they both tell me that Fname is an undeclared identifier.

[phiefer3]

I tried both, and they both tell me that Fname is an undeclared identifier.

check my edit, and try that:

&(this->Per.Fname[0]);

if that doesn't work, then I don't know.

by the way, the way you're class is set up, it would might be easier to make your employee class inherit from the person class, instead of containing a personclass object.

[Hypnotik]

check my edit, and try that:

&(this->Per.Fname[0]);

Well that is atleast not giving me the error. Now I receive the about a line and a half of garbage symbols.

After I input the information, I print it out (within) that function to make sure it's in the right place...and it seems to be saving in the right place. But when I go to this function (SetFname) something is getting lost.

J

[weaknessforcats]

Sorry about missing Per. I didn't compile my code.

I did compile this code:

#include <iostream>
using namespace std;
struct Person
{
    char Fname[20],Lname[20];
    float age;
    int ssn[9],enumber[9];
};
class Employee
{
private:
    int enumber[9],ssn[9];
    float wage;
    char job_title[10];
    Person Per;
public:
    const char* GetFname();
    void SetFname(char* arg);
};
const char* Employee::GetFname()
{
     return Per.Fname;
}
void Employee::SetFname(char* arg)
{
    strcpy(Per.Fname, arg);
}
 
int main()
{
    Employee emp;
    emp.SetFname("weaknessforcats");
    cout << emp.GetFname() << endl;
}
 

and it works.

There is no difference between Per.Fname and &Per.Fname[0]. It is just two ways of saying the same thing.