How do i change this into a function?

Ok, i'm having real issues with functions, can anyone help me or make suggestions as to how i change this to a function?

Code:

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

float deposit(float x);
float withdrawal(float y);
float transfer(float z);
bool funds;

using namespace std;

void main()

{	string filename, account, transaction;
	fstream file;
	float checking, savings, amount;

	cout << "Welcome to the Bank!" << endl << endl;
	cout << "Please Enter your name: ";
	cin >> filename;

	file.open(filename.data(),ios::in);

	checking=0;
	amount=0;
	savings=0;
	cout << fixed << setprecision(2) << endl << endl;
	cout << left << setw(21) << "Transaction " << left << setw(8) << "Amount " << left << setw(9) << "Savings " << left << setw(9) << "Checking " << endl;
	cout << "-------------------- " << "------- " << "-------- " << "--------" << endl;
	
	while(!file.eof())
	{

		file >> account;
		file >> transaction;
		file >> amount;
	
		cout << account << " " << left << setw(12) << transaction << " ";
	
//CHECKING AREA
		
		if(account=="checking")
		{
			if(transaction=="deposit")
			{
				checking = amount + checking;
				cout << right << setw(6) << amount;
				cout << right << setw(9) << savings;
				cout << " " << right << setw(8) << checking << endl;
			}
			else if(transaction=="withdrawal")
			{
				if(amount<checking)
				{
					funds=true;
				}
				else
				{
					funds=false;
				}

				if(funds)
				{
					checking = amount - checking;
					cout << right << setw(6) << amount;
					cout << right << setw(8) << savings;
					cout << " " << right << setw(8) << checking << endl;
				}

				else if(!funds)
				{
					cout << right << setw(6) << amount << " ";
					cout << right << setw(10) << "Insufficient Funds" << endl;
				}

			}
			else if(transaction=="transfer")
			{
				checking = checking - amount;
				savings = amount + savings;
				cout << right << setw(6) << amount;
				cout << right << setw(9) << savings;
				cout << " " << right << setw(8) << checking << endl;
			}
		}

//SAVINGS AREA

		else if(account=="savings")
		{
			if(transaction=="deposit")
			{
				savings = amount + savings;
				cout << right << setw(7) << amount;
				cout << right << setw(9) << savings;
				cout << " " << right << setw(8) << checking << endl;
			}
			else if(transaction=="withdrawal")
			{
				savings = savings - amount;
				cout << right << setw(7) << amount;
				cout << right << setw(9) << savings;
				cout << " " << right << setw(8) << checking << endl;
			}
		}
	};
cout << endl;



}

I know that true/false thing is redundant, but our teacher wanted us to use a bool to determine if theres enough funds according to true and falses. There are supposed to be three functions, a deposit, withdrawal, and transfer. I believe the trasnfer needs two paramaters.

I tried cutting out a deposit if statement and try to put that in a function, but it wouldnt work.

any help much apreciated.

here is what the out put looks like. The code works, i'm just confused as to how i would make that a function.

Welcome to the Bank!

Please Enter your name: c:\mark.txt


Transaction Amount Savings Checking
-------------------- ------- -------- --------
checking deposit 50.00 0.00 50.00
savings deposit 100.00 100.00 50.00
savings withdrawal21.50 78.50 50.00
checking transfer 42.68 121.18 7.32
checking deposit 14.95 121.18 22.27
checking withdrawal25.00 Insufficient Funds
savings deposit 1.25 122.43 22.27
checking deposit 25.00 122.43 47.27

Press any key to continue

http://35.9.168.96/C++/Program11.doc

is the url of the assignment to clairfy things.

> I know that true/false thing is redundant, but our teacher wanted us to use a bool
Maybe so, but that's no reason for it to be global.

> void main
http://faq.cprogramming.com/cgi-bin/...&id=1043284376

> while(!file.eof())
This is also in the FAQ

> I tried cutting out a deposit if statement and try to put that in a function, but it wouldnt work.
It would have been nicer if you had at least posted your attempt. Now we've no idea how close you are.

Perhaps

Code:

float do_savings ( string transaction, float savings, float amount ) {
	if(transaction=="deposit")
	{
		savings = amount + savings;
		cout << right << setw(7) << amount;
		cout << right << setw(9) << savings;
		cout << " " << right << setw(8) << checking << endl;
	}
	else if(transaction=="withdrawal")
	{
		savings = savings - amount;
		cout << right << setw(7) << amount;
		cout << right << setw(9) << savings;
		cout << " " << right << setw(8) << checking << endl;
	}
	return savings;
}

Then in main, you have

Code:

else if(account=="savings") {
  savings = do_saving( transaction, savings, amount );
}