Multiple values for function

[youngnito]

Hello guys I have a function that calculates a destination points for x and y.. and when I have the actual values I want to send them back to my main program to have them displayed as results.. but I am running into issues just because I am unsure how to do it.. My professor said to pass them through reference parameters but I am unsure how to

any help would be appreciated! Thanks in advance!

#include <iostream>
#include <math.h>
using namespace std;

void displayMenu(void);
double engineerOne(double pointxI, double pointxII, double pointyI, double pointyII);
double engineerTwo(double pointxI, double pointxII, double pointyI, double pointyII);
double engineerThree(double verticalAngleD, double velocityMile);
void engineerFour(double pointxI, double pointyI, double pointDistance, double angleDegree, double destinationX, double destinationY);
void getPoints(double& pointx, double& pointy);
void custServiceOne(double& pointxI, double& pointxII, double& pointyI, double& pointyII);
void custServiceTwo(double& pointxI, double& pointyI);
void custServiceThree(double& verticalAngleD, double& velocityMile);
void custServiceFour(double& pointxI, double& pointyI, double& pointDistance, double& angleDegree);

int main()
{
	char again;
	int programChoice;
	double pointxI, pointxII, pointyI, pointyII, verticalAngleD, velocityMile,
		pointDistance, angleDegree, TwopointDistance, 
		degreeAngle, distanceFeet,
		destinationX, destinationY;


	cout << endl << "Compute Different Awesome Equations" << endl << endl;

	do 
	{
		do 
		{
			displayMenu();

			cout << "Please enter your selection: ";
			cin >> programChoice;

			if (programChoice > 5 || programChoice <= 0)
			{
				cout << endl << "Please enter a number from 1 to 5";
				cout << endl << endl;
			}
		}
		while (programChoice > 5 || programChoice <= 0);		
		
		if (programChoice == 1)
		{
			custServiceOne(pointxI, pointxII, pointyI, pointyII);
		}
		else if (programChoice == 2)
		{
			custServiceTwo(pointxI, pointyI);
		}
		else if (programChoice == 3)
		{
			custServiceThree(verticalAngleD, velocityMile);
		}
		else if (programChoice == 4)
		{
			custServiceFour(pointxI, pointyI, pointDistance, angleDegree);
		}

		if (programChoice == 1)
		{
			TwopointDistance = engineerOne(pointxI, pointxII, pointyI, pointyII);
		}
		else if (programChoice == 2)
		{
			degreeAngle = engineerTwo(pointxI, pointxII, pointyI, pointyII);
		}
		else if (programChoice == 3)
		{
			distanceFeet = engineerThree(verticalAngleD, velocityMile);
		}
		else if (programChoice == 4)
		{
			engineerFour(pointxI, pointyI, pointDistance, angleDegree, destinationX, destinationY);
			engineerFour(pointxI, pointyI, pointDistance, angleDegree, destinationX, destinationY);

                  //I need to have engineer four calculate these two destinations here
		}

		if (programChoice == 1)
		{
			cout << "The distance between your two points is: "
				<< TwopointDistance << endl;
		}
		else if (programChoice == 2)
		{
			cout << "The horizontal angle from the first point to the" 
				" second point is: " << degreeAngle << endl;
		}
		else if (programChoice == 3)
		{
			cout << "The horizontal distance (in feet) the object" 
				" traveled is: " << distanceFeet << endl;
		}
		else 
		{
			cout << "The destination point is ("
				<< destinationX << "," << destinationY << ")" << endl;

                     // I need to display them here like (x,y) just unsure how
		}
		
		cout << endl << "Would you like to do another calculation (y/n)? ";
		cin >> again;
	}
	while (again == 'y');

	return 0;
}

void displayMenu(void)
{
	cout << endl;
	cout << "Choose from the following options: " << endl;
	cout << "(1) Compute the distance between two points" << endl;
	cout << "(2) Compute the horizontal angle of two points" << endl;
	cout << "(3) Compute the (horizontal distance (in feet)" << 
		" that an object travels" << endl;
	cout << "(4) Compute the destination point" << endl;
	cout << "(5) Exit the program" << endl;
}

double engineerOne(double pointxI, double pointxII, double pointyI, double pointyII)
{
	double TwopointDistance; 

	TwopointDistance = sqrt(pow(pointxII - pointxI, 2) +
				pow(pointyII - pointyI, 2));

	return (TwopointDistance);
}

double engineerTwo(double pointxI, double pointxII, double pointyI, double pointyII)
{
	const double PI = 3.14159;
	double distanceX, distanceY, radianAngle, degreeAngle;

	distanceX = pointxII - pointxI;
	distanceY = pointyII - pointyI;

	if (distanceX > 0)
	{
		radianAngle = atan(distanceY / distanceX);
	}
	else if (distanceX < 0)
	{
		radianAngle = atan(distanceY / distanceX) + PI;
	}
	else if (distanceX == 0 && distanceY >= 0)
	{
		radianAngle = PI/2;
	}
	else
	{
		radianAngle = -PI/2;
	}

	degreeAngle = radianAngle * (PI / 180);

	return degreeAngle;
}

double engineerThree(double verticalAngleD, double velocityMile)
{
	const double PI = 3.14159, FeetperMile = 5280, SecperHour = 3600, gravity = 32.172;
	double velocityFeet, verticalAngleR, distanceFeet;

	verticalAngleR = verticalAngleD * (PI / 180);

	velocityFeet = velocityMile * (FeetperMile / SecperHour);

	distanceFeet = pow(velocityFeet, 2) * 
		sin(2 * verticalAngleR) / gravity;

	return distanceFeet;
}

//engineer four is the one I am having trouble with
void engineerFour(double pointxI, double pointyI, double pointDistance, double angleDegree, double destinationX, double destinationY)
{
	const double PI = 3.14159;
	double angleRadian, distanceX, distanceY;

	angleRadian = angleDegree * (PI / 180);
	
	distanceX = pointDistance * cos(angleRadian);

	distanceY = pointDistance * sin(angleRadian);

	destinationX = pointxI + distanceX;

	destinationY = pointyI + distanceY;
         //I get two destinations one for x and one for y

}

void getPoints(double& pointx, double& pointy)
{
	cout << endl << "Please enter your x point: ";
	cin >> pointx;

	cout << endl << "Please enter your y point: ";
	cin >> pointy;
}

void custServiceOne(double& pointxI, double& pointxII, double& pointyI, double& pointyII)
{
	cout << endl << "Please enter your first set of points: " 
		<< endl;

	getPoints(pointxI, pointyI);

	cout << endl << "Please enter your second set of points: " 
		<< endl;

	getPoints(pointxII, pointyII);
}

void custServiceTwo(double& pointxI, double& pointyI)
{
	cout << endl << "Please enter your set of points: "
		<< endl;

	getPoints(pointxI, pointyI);
}

void custServiceThree(double& verticalAngleD, double& velocityMile)
{
	do
	{
		cout << endl << "Please enter your elevation angle: ";
		cin >> verticalAngleD;

		if (verticalAngleD <= 0 || verticalAngleD >= 90)
		{
			cout << endl << "Please input an angle between 0 - 90 degrees";
			cout << endl << endl;
		}
	}
	while (verticalAngleD <= 0 || verticalAngleD >= 90);

	do 
	{
		cout << endl << "Please enter the velocity: ";
		cin >> velocityMile;

		if (velocityMile <= 0)
		{
			cout << endl << "Please enter a positive velocity";
			cout << endl << endl;
		}
	}
	while (velocityMile <= 0);
}

void custServiceFour(double& pointxI, double& pointyI, double& pointDistance, double& angleDegree)
{
	cout << endl << "Please enter your set of points: " << endl;

	getPoints(pointxI, pointyI);
	
	do 
	{
		cout << endl << "Please enter your distance: ";
		cin >> pointDistance;

		if (pointDistance <= 0)
		{
			cout << endl << "Please enter a positive distance";
			cout << endl << endl;
		}
	}
	while (pointDistance <= 0);

	do 
	{
		cout << endl << "Please enter your horizontal angle: ";
		cin >> angleDegree;

		if (angleDegree < 0 || angleDegree > 360)
		{
			cout << endl << "Please enter an angle between 0 - 360 degrees";
			cout << endl << endl;
		}
	}
	while (angleDegree < 0 || angleDegree > 360);
}

Again thanks in advance!

[keskiverto]

You do have, for example, a function
void getPoints(double& pointx, double& pointy);
Could you try to explain its details? What parameter types does it take?

Or more generally, what do you think the "by value" and "by reference" to mean?

[youngnito]

I am probably explaining what I want to do wrong and I am sorry for that lol.

So generally I know that custServiceFour gets my information pointxI, pointyI, pointDistance and angleDegree and that sends it over to my engineerFour, but where I am having issues at is displaying the results for my engineerFour.

so I worked out the calculations:
pointxI = 5
pointyI = 8
pointDistance = 30
angleDegree = 45

I would get
destinationX = 26.21322
destinationY = 29.21319

generally in my main I want to display these points

cout << "Your destination points are: (" << destinationX << "," << destinationY << ")"

How would I pass the values that the engineer function calculates to the main function to display them here?

hope that makes more sense

[keskiverto]

Look at the declarations of custServiceFour and engineerFour. How do they differ?
Look at http://www.cplusplus.com/doc/tutorial/functions2/

[youngnito]

Thanks for that keskiverto I went to look through my program and just threw the & in front of destinationX and destinationY and it worked.