Need help involving vectors and classes

[bwoo]

I am having trouble putting data from a txt file onto a vector of a class.
For instance.

class employee{
setname(string)
{
some code
}
getname ()
{
some code
}
setid(int)
{
some code
}
getid ()
{
some code
}
};
int main()
{
int num = 0;
 vector<employee> vec;

ifstream instream;
instream.open(somefile);

while(!instream.eof())
{
  tempname;
  instream >> tempname;
vec[num].setname(tempname);
  num++;
}

}

How would use my setname function in my class using my vector?
I tried doing vec[num].setname(tempname) but it doesn't work. I know it does not work because I have to use .push back for a vector but I don't know exactly how to pushback using the setname functioncall. Thank you for the help!! Really appreciate it.

[Esslercuffi]

you have to create the new vector element first, then call the .setname() member. You can't have the setname() member create the object. that's a chicken and egg problem.

[bwoo]

sorry, but what do you mean by "creating the new vector element first"? I don't really understand what that means

[Esslercuffi]

how you'd really want to do this is by having a constructor of employee which takes a string argument for the name. once that's implemented, vec.push_back( tempname ); should work.

what you're doing above vec[num].setname( tempname ); will only work to change an existing element's name.

[bwoo]

Ahh, I see. Sorry to bother you, but I have another question. Let's say i have more than one constructor that takes a string argument. How would I differentiate between the two?
Say i have 2 constructors
Employee (string firstname)
and
Employee(string lastname).
How would I input my data into separate ones because they both take a single string argument.

[Esslercuffi]

You can't really. you could have a constructor take a single string:
Employee( string firstname )

and another constructor which takes two strings:
Employee( string firstname, string lastname )

but can't have two that only take a single string argument. You would have to find some other way to differentiate the number and or type of arguments.

[bwoo]

so going back to my original problem, how would I use the setname function without using a constructor since I have multiple functions using only one string as a parameter?

[Esslercuffi]

something like this should work

while(!instream.eof())
{
	tempname;
	instream >> tempname;
	
	vec.push_back(); // create new element
	vec[vec.size() - 1].setname(tempname);
}

[bwoo]

for vec.push_back() you need an argument. It doesn't work if I compile it as is

[Esslercuffi]

oh yeah... try this.
vec.push_back( employee temp );

just creates a new empty employee object to pass.

[bwoo]

yea, same issue. Doesn't compile correctly