Anonymous

/* 

Airplane Problem Solver.

"An airplane goes at X miles per hour with no wind resistance.  It travels Y amount of miles with the wind and Z amount 
of miles against the wind, in T amount of time.  How fast was the wind blowing?"

We will need to transform this word problem into a quadratic equasion, and then solve it.


Quadratic Equasion is

x = -b +/- sqrt( (b)squared - 4(A)(C) ) / (2)(A)

We will get two answers for this, a negative and a positive answer.  Since we cant have negative miles per hour,
the answer will be the positive one.
*/

//Quadratic Equasion formula variables
float A, B, C;  //floats because they may have a decimal point. Integers are not needed.
float f1,f2,f3;  //intermediate function
float X1, X2;   //two possible outcomes.

#define BSQRD B * B  // ^ is the XOR function, not Exponent.  We learned this the hard way.

//d = rt, or t = d/r
float speed, distanceW, distanceA, time;
int iChoice; //lets make this a global variable

#define QUADPLUS -B + sqrt ( BSQRD - 4 * A * C )
#define QUADMINUS -B - sqrt ( BSQRD - 4 * A * C )

int Greeting()
{
	printf("Welcome to the Algebra Solver! \n");
	printf("Programmed by Paulius Trimakas \n");
	printf("What would you like to do? \n");
	printf("1. Solve a Quadratic Equasion\n");
	printf("2. Solve the Airplane Problem\n");
	cin >> iChoice;

	return iChoice;
}

void QuadraticEquasion()
{
	cout << "What is A?" << endl;
	cin >> A;

	cout << "What is B?" << endl;
	cin >> B;

	cout << "What is C?" << endl;
	cin >> C;

	f1 = QUADPLUS;
	f2 = QUADMINUS;
	f3 = (2 * A);

	X1 = f1 / f3;
	X2 = f2 / f3;

	printf("Your answers are: \n");
	printf("%f \n %f\n",X1, X2);
}

float GetAirplaneVars()
{
	cout << "What is the speed of the airplane in still air?\n" << endl;
	cin >> speed;

	cout << "What is the distance against the wind?\n" << endl;
	cin >> distanceA;

	cout << "What is the distance with the wind?\n" << endl;
	cin >> distanceW;

	cout << "What is the total time traveled (in hours)\n" << endl;
	cin >> time;

	return speed, distanceA, distanceW, time;
}


void SolveAirplane()
{
	
	//fuck it, we'll just do the actual distribution.

	//our equasion is distanceA(speed + r) + distanceW(speed - r) = time (speed + r)(speed - r)
	//we need to find r, so r = x (for quadratic equasion)

	float temp1, temp2, temp3,temp4,temp5,temp6,temp7,temp8,temp9;

	temp1 = distanceA * speed;
	temp2 = distanceA; //distanceA + r
	temp3 = distanceW * speed;
	temp4 = -distanceW; //distanceW - r
	temp5 = speed * speed;
	temp6 = time * temp5;
	temp7 = temp1 + temp3;
	temp8 = temp2 + temp4;
	temp9 = temp7 - temp6;

	printf("Your quadratic equasion is: \n");
	printf("%f x^2 + %f x + %f\n",time,temp8,temp9);

	//And now, we go for the quadratic equasion itself to give us the speed of the wind.

	A = time;
	B = temp8;
	C = temp9;

	f1 = QUADPLUS;
	f2 = QUADMINUS;
	f3 = (2 * A);

	X1 = f1 / f3;
	X2 = f2 / f3;

	printf("The speed of the wind is (choose the positive answer):\n");
	printf("%f\n%f\n",X1,X2);

}


int _tmain(int argc, _TCHAR* argv[])
{
	Greeting();
	if(iChoice == 1)
	{
		QuadraticEquasion();
	}
	else if(iChoice == 2)
	{
		GetAirplaneVars();
		SolveAirplane();
	}
	system("pause");
	return 0;
}