// Zeinalipour-Yazti Demetrios
// csyiazti
// cs10xx -  Lab Sec#25-#29
// lab8
/*		
 * This program defines a function that finds and returns the distance between
 * two points. The function should take as parameters the x and y coordinates 
 * of point1 and the x an y coordinates of point2. The coordinates are 
 * floating-point values. The program allows the user to find the distance
 * between as many points as they want. Each output is outputted as a 
 * floating-point value showing 3 digits to the right of the decimal.
 */

#include <iostream>
#include <cmath>
#include <iomanip>

using namespace std;



/* Get value from user along with error checking etc
 * @return : the FLOAT value given by the user
 */
float getfloat(char name[])
{
	float val;
	cout << "Please enter floating point value (" << name << ") : ";
	cin >> val;
	while (cin.fail())
	{
		cout << "#ERROR - Only floating point values are allowed!\n";
		cin.clear();
		cin.ignore(80, '\n');
		cout << "Please enter floating point value (" << name <<  ") :";
		cin >> val;
	}
	return val;
}

/* This function returns us the distance between 2 points
 * @return : the distance bete number
 */
float distance(float x1, float y1, float x2, float y2)
{
    double temp1 = pow(x2-x1, 2);
	double temp2 = pow(y2-y1, 2);

	// return the result of the given formula
	return sqrt(temp1+temp2);

}


/* This function asks the user to select the char "y" or "n" 
 * @return : y for yes
 *           n for no
 */
char doAgain()
{    /* defining local scope variables*/
     char value;

     cout << "\nDo you want to run the program again (y/n) ?:  ";
     cin >> value;
     while (cin.fail() || !(value=='y' || value=='n'))
	 {
		 cout << "#Error - only (y/n) are accepted!\n";
		 cin.clear();
		 cin.ignore(80, '\n');
		 cout << "Do you want to run the program again (y/n) ? :  ";
		 cin >> value;
	 }
	 cout << endl;
     return value;
}



void main()
{
	/* define variables */
	float result;          /* the result                  */	
	float x1, y1, x2, y2;  /* the coordinates of point1, point2 respectively */ 

	/* define functions & procedures*/
	float getfloat(char name[]); /* get a correct float value from user	*/
	float distance(float x1, float y1, float x2, float y2);
	char doAgain(); /* returns 'y' or 'n' to the question whether to continue  */
	
	
	cout << "Distance Calculator by Demetris Zeinalipour - Lab 8 \n\n";
	// run the program as many times as the user wants		
	do 
	{	
		// get the input from user in a function-fashion way 		
		x1 = getfloat("x1");
		y1 = getfloat("y1");
		x2 = getfloat("x2");
		y2 = getfloat("y2");

		/* calculate the result*/	
		result = distance(x1, y1, x2, y2);
		
		// output result
		cout << setprecision(3) << setiosflags(ios::fixed | ios::showpoint) 
		     << "\n\nThe distance of (" << x1 << "," << y1 << ") to ("
					  					<< x2 << "," << y2 << ") is : " 
										<< result; 		

	} while (doAgain()=='y');

}