Void function problems

[Amy269]

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


//functions
double getSalary();
void calcFedTaxes(double salary, int FWT, int FICA, double &totNetPay); 
void calcNetPay(double netPay, int FWT, int FICA, double &totNetPay);
void displayInfo(int FWT, int FICA, double &totNetPay);
void totNetPay(double &totNetPay, double netPay);
int main()
{
	//declare variables
	double salary		= 0.0;
	const double FWT	= 0.2;
	const double FICA	= 0.08;
	double totNetPay	= 0.0;
	double netPay		= 0.0;

	salary = getSalary();

	while (salary > 0)
	{
		calcFedTaxes(salary, FWT, FICA, totNetPay);
		calcNetPay(netPay, FWT, FICA, totNetPay);
		displayInfo(FWT, FICA, totNetPay);
		salary = getSalary();
	}//end while

	cout << "Total net pay is: " << totNetPay << endl;

	system("pause");
	return 0;
}

//defining functions

double getSalary()
{
	double salaryAmt = 0.0;
	cout << "Enter salary amount: (-1 to stop) ";
	cin >> salaryAmt;
	return salaryAmt;
}

void calcFedTaxes(double salary, int FWT, int FICA, double &totNetPay)
{
	FWT = salary * .2;
	FICA = salary *.08;
}// end of calcFedTaxes

void calcNetPay(double netPay, int FWT, int FICA, double &totNetPay)
{
	totNetPay = netPay + FWT + FICA;
}// end of CalcNetPay

void displayInfo(int FWT, int FICA, double &totNetPay)
{
	cout << FWT << endl;
	cout << FICA << endl;
	cout << totNetPay << endl;
}

void totNetPay(double &totNetPay, double netPay)
{
	totNetPay += netPay;
}

The problem I am having is the calculations. When I run the program, doesn't do any of the calculations

[CosminNTG]

At the first view, it should work properly. Try to put a part of the code on comment and see if work all the functions one by one. You will find the mistake more fast.

[Amy269]

I figured it out, or maybe a way for it to work. I changed this:

{
	cout << FWT << endl;
	cout << FICA << endl;
	cout << totNetPay << endl;
}

to this:

{
	FWT = salary *.2;
	cout << "FWT is: " << FWT << endl;
	FICA = salary * .08;
	cout << "FICA is: " << FICA << endl;
	totNetPay = salary - FWT - FICA;
	cout << "Net pay is: " << totNetPay << endl;
}

After this change it worked perfect!

[CosminNTG]

Advice: don't use system("pause") any more. It slows your application and can make some damage at the computer's intern structure.

[Peter87]

What difference does it make if system("pause") is slow? It's not slow enough to be noticeable. And what is the intern structure that is damaged? I don't understand.

[Mathhead200]

I don't know what CosminNTG is talking about, but there are some good reasons to not use system(...); in production code. One simple example would be that system("pause"); only works in windows, and there are non-OS specific ways to do the same thing. Read: http://cplusplus.com/forum/beginner/1988

Also note that chances are if your writing code that uses the standard streams (cout, cin, and cerr) and not a text based UI, you don't want to pause the program before exit anyway. These programs may (and arguable should) be run directly from the command prompt or a batch file/shell script, in which case you don't want to hard code a statement like that in the executable.

[Lynx876]

void calcFedTaxes(double salary, int FWT, int FICA, double &totNetPay)
{
	FWT = salary * .2;
	FICA = salary *.08;
}// end of calcFedTaxes 

Pass the variables to be changed, by reference. So they are changed in the function that called it.

void calcFedTaxes(double salary, int &FWT, int &FICA, double &totNetPay)
{
	FWT = salary * .2;
	FICA = salary *.08;
}// end of calcFedTaxes 

EDIT:
Also, You're doing FWT = salary * .2;. And you're saving to an int. You wont have the correct number.