//Program to compute the area of a right triangle
#include <iostream>
#include <iomanip>
#include <fstream>
 
 
 
//Declare std
using std::cout;
using std::cin;
using std::endl;
using std::ios;
using std::cerr;
using std::ofstream;
 
//Function Prototype
double findarea (double,double);
 
//Start the program
int main ()
{
 
//Declare the variables
	double a; //side a
	double b; //side b
	double d; //area
 
 
//Open the file for output
	ofstream datafile ("program.txt", ios::out);
 
//Error routine if file can not be created
	if (!datafile) {
		cerr << "File could not be opened" << endl;
		exit (1);
	}
 
//Initialize a 
	a=1;
 
//Describe program to user
	cout << "This program will compute the area of a right triangle.\n\nSet side a or b to 0 or less to end the program.";
	datafile << "This program will compute the area of a right triangle.\n\nSet side a or b to 0 or less to end the program.";
 
//Begin the WHILE loop to set sentinal value to loop the program
	while (a>0){
 
 
//Get a 
		cout << "\n\nEnter the length of side a: " << endl;
		cin >> a;
		datafile << "\n\nSide a is: " << a << endl;
 
//Use an IF to dictate the behavior of the program if a>0 and get b
		if (a>0){			
			cout << "\nEnter the length of side b: " << endl;
			cin >> b;
			datafile <<"Side b is: " << b << endl;
 
//Allow for b<=0
			if (b<=0){
				cout << "\n\nYou have ended the program." << endl;
				datafile << "You have ended the program." << endl;
				break;
			}			
 
			d=findarea(a,b);
 
			cout << "\nThe area is: " << d << endl;
			datafile << "The area is: " << d << endl;
 
//End IF
		}
 
//Start ELSE to allow output that tells the user they have ended the program
		else {
			cout << "\n\nYou have ended the program." << endl;
			datafile << "You have ended the program." << endl;
 
//End ELSE 
		}
 
 
//End WHILE
	}
 
//End program
		return 0;
 
}
 
 
 
double findarea (double q,double r,double s) {
	s=(q*r)/2;
	return s;
}