easy c++ question: calculate employee's net pay

#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <stdio.h>
#include <iostream.h>

using namespace std;

#define TAX_RATE .30

int main(void) {
	char 	*first,
       		*last, 
		*ssn,
		*test,
		*final_output;
	float 	hours=0,
		pay_rate=0,
		gross=0,
		taxes=0,
		net=0;

	/*-- lets create the variables --*/
	final_output = new char[1024];
	first = new char[50];
	last = new char[50];
	ssn = new char[12];
	test = new char[1024];

	/*-- start the loop --*/
	do {
		/*-- get first & last name --*/
		cout << "First Name: ";
		cin >> first;
		cout << "Last Name: ";
		cin >> last;
		
		/*-- get ssn with error checking on length only --*/
		do {
			cout << "SSN: ";
			cin >> ssn;
			if (strlen(ssn) == 11)
				break;
			else
				cout << "Invalid ssn.  Must be in format 999-99-9999";
		} while (1);
			
		/*-- 
			get pay rate with error checking on
			null and 0 values
		--*/
		do {
			cout << "Pay Rate: ";
			cin >> test;
			if (test == NULL) 
				cout << "Invalid pay rate.";
			else if(atof(test) != 0) 
				break;
			else
				cout << "Invalid pay rate.";			
		} while (1);
		pay_rate=atof(test);
			
		/*--
			get hours worked with error checking on
			null and 0 values
		--*/
		do {
			cout << "Hours Worked: ";
			cin >> test;
			if (test == NULL)
				cout << "Invalid amount of hours.";
			else if(atof(test) !=  0)
				break;
			else
				cout << "Invalid amount of hours.";
		} while (1);
		hours=atof(test);

		/*-- calculate values --*/		
		gross=hours*pay_rate;
		taxes=gross*TAX_RATE;
		net=gross-taxes;

		/*-- set out precision --*/
		cout.precision(2);
		cout.setf(ios::fixed | ios::showpoint);
		
		/*-- create output --*/
		sprintf(final_output,"\n\n%s %s ssn(%s)\n------------------------------\n",
				first,last,ssn);
		cout << final_output;
		cout << "Gross: " << gross << endl;
		cout << "Taxes: " << taxes << endl;
		cout << "Net:   " << net << endl << endl;

		/*-- do another? --*/
		cout << "Calculate Another? (y/n)?";
		cin >> test;

		/*-- check first value of string for y/Y --*/
	} while (!strncasecmp(test,"y",1));

	/*-- return memory to the heap --*/
	delete [] first;
	delete [] last;
	delete [] ssn;
	delete [] test;
	return 1;
}