Need hand with file input/Output

Howdy all,
I am having a bit a trouble understanding how file input and output works. I am working on a Lab for Intro to C++ and I need to work with input output and loops:


· Process input from 2 files: salesDay.dat and salesNight.txt
· Must allow the user to type the name for the input file so that the name can be stored in a variable. This allows you to process either file with no changes to your program.
· Will input 4 salesman from the day crew and 4 from the night crew
· Will use a counter and accumulator
· Will compute and print the average sales.
· Will print 2 salesman if there is a tie. (Check the sample screen). We will assume that no more than 2 salesman will ever have the same sales figure but 2 might.
· Will store the salesman's ID (a number) and his sales figure for printing later.
· Will use at least one switch statement.
· Format all output as closely as possible to the sample screens.


That's what I need to do. Now I have started writing the code but I am stuck at opening up the input files. This is what I have so far.

Code:

#include <string>
#include <iomanip>
#include <iostream>
#include <fstream>

using namespace std;



int main()

{

	string winner;
	int salesmanId;
	int salesmanNumber;
	string winningMessage;
	string filename;
	ifstream inData;
	ofstream outData;



	


	cout<<"Please enter the name of the data file: ";
	getline(cin,filename);

	inData.open("salesday.dat");
	

    


    cout<<setw(25)<<"Salesman Contest"<<endl;
    cout<<endl;
	cout<<setw(25)<<"October 2003"<<endl;
	cout<<endl;
	cout<<setw(15)<<"And the winner is: "<<endl;
	cout<<endl;
	cout<<"Amount of sales: "<<endl;
	cout<<endl;



}

I don't want answers as I want to figure it out myself. But y question is is this correct for inputting a file? Does the input get stored in a variable? I am kinda looking for a pointer in the right direction. Again, I wanna figure this out but I'm a little cinfused with file input and output.


P.S. The tutorial wasn't much help

I am trying to understand the concept here......also where do I need to put the file in order for my program to read it?

indata >> dump;
outdata << dump;

note: dump should be a char string, char dump[];

That is how you input.output, along with everything else you did. You'll also want:
indata.close();
outdata.close();

getline(cin,filename); //whats this for?

I can't quite understand what you are trying to do, but I hope the above was of help.

I'm not sure if I know what I'm trying to do either. Basically I want to read the input files and process the information. Basically what I need to know is how do I read and process information once I open a file?