/***************************************************************/
/* 						  Laboration 1 i C++ 							*/
/***************************************************************/
/* 	Program som beräknar :												*/
/* 	1. Förstagradsekvationer											*/
/* 	2. Andragradsekvationer 											*/
/* 	3. Newton-Raphson 													*/
/* 	4. Pythagoras sats													*/
/* 	5. Cosinussatsen														*/
/***************************************************************/
/* 						Crille & Robin 971009							*/
/***************************************************************/

#include "header.h"

/***************************************************************/
// Säker inmatning
/***************************************************************/
float mataIn()
{
	char buffer[BUFFERSIZE];
	float f;
	do
	{
		cin >> buffer;
		if (strcmp(buffer,"0") == 0)
			return 0.0;
		else
		{
			f = atof(buffer);
			if (f!=0)
				return f;
			else
				cout <<"Inget tal, försök igen: ";
		}
	}while (!f);
}

/***************************************************************/
// Förstagradsekvation
/***************************************************************/
void funk1()
{
	float a,b,x;

	clrscr();
	cout <<"Förstagradsekvation"<< endl;
	cout <<"-------------------\n\n";
	cout <<"Ekvationen har formen ax + b = 0"<< endl;
	cout <<"\nAnge a: ";
	a = mataIn();
	cout <<"\nAnge b: ";
	b = mataIn();
	if (a != 0)
	{
		x = (-b / a);
		cout <<"\nRoten är " << x << endl;
	}
	else
	cout <<"\nDet där är ingen ekvation!\n\n\n";
	cout <<"\nTryck på någon tangent !";
	getch();
}

/***************************************************************/
// Andragradsekvation
/***************************************************************/
void funk2()
{
	float a,b,c,d,x1,x2,x3;

	clrscr();
	cout <<"Andragradsekvation\n";
	cout <<"------------------\n\n";
	cout <<"Ekvationen har formen ax^2 + bx + c = 0\n";
	cout <<"Ange a: ";
	a = mataIn();
	cout <<"\nAnge b: ";
	b = mataIn();
	cout <<"\nAnge c: ";
	c = mataIn();
	if (a == 0)
	{
		if (b != 0)
		{
			x1 = (-c / b);
			cout <<"Roten är: " << x1 << endl;
		}
		else
			cout <<"Det där är ingen ekvation !";
	}
	else
	{
		if (pow((b / (2*a)),2) - (c / a) < 0)
			cout <<"\nRötterna är inte reella\n\n\n";
		else
		{
			d=(b / (2 * a));
			x2= ( -d ) + sqrt (pow (d,2) - (c / a));
			x3= ( -d ) - sqrt (pow (d,2) - (c / a));
			cout <<"\nRot 1: "<< x2 << endl;
			cout <<"Rot 2: "<< x3 << endl;
		}
	}
	cout <<"Tryck på någon tangent !";
	getch();
}

/***************************************************************/
// Newton-Raphson
/***************************************************************/
void funk3()
{
	double koeff[MAXGRAD];
	double f,d,x,x0;
	int i,a = 0,grad;

	clrscr();
	cout <<"Newton - Raphson"<< endl;
	cout <<"----------------\n"<< endl;
	cout <<"Mata in gradtal: ";
	grad = mataIn();
	for (i = 0 ; i <= grad ; i++)
	{
		cout <<"\nMata in koefficienten för x^"<< i << " ";
		koeff[i] = mataIn();
	}
	cout <<"Mata in ett startvärde: ";
	x = mataIn();
	do
	{
		x0 = x;
		f = 0;
		for (i = 0 ; i <= grad ; i++)
			f = f + koeff[i] * pow (x0 , i);
		d = 0;
		for (i = 1 ; i <= grad ; i++)
			d = d + koeff[i] * i * pow (x0 , i-1);
		x = x0 - f/d;
		a++;
	}while ((a <= VARV) && (fabs(x - x0) > fabs(x * DIFF)));
		if (fabs (x - x0) < fabs(x * DIFF))
		cout <<"\nRoten är: "<< x << endl;
	else
		cout <<"\nRoten ej funnen efter "<< VARV <<" beräkningar.\n";
	getch();
}

/***************************************************************/
// Pythagoras sats
/***************************************************************/
void funk4()
{
	char sort;
	float a,b,c;

	clrscr();
	cout <<"Är hypotenusan känd? [j/n]";
	cin >> sort;
	if (sort == 'n')
	{
		clrscr();
		cout <<"Pythagoras sats\n";
		cout <<"---------------\n\n";
		cout <<"\nAnge ena sidan i triangeln: ";
		a = mataIn();
		cout <<"\nAnge andra sidan i triangeln: ";
		b = mataIn();
		if (a < 0 || b < 0)
		{
			cout <<"Otillåten inmatning !"<< endl;
			getch();
		}
		else
		{
			c = sqrt(pow(a,2) + pow(b,2));
			cout <<"\nHypotenusan är: "<< c <<"\n\n\n"<< endl;
			cout <<"Tryck på någon tangent !";
			getch();
		}
	}
	else
	{
		clrscr();
		cout <<"Pythagoras sats\n";
		cout <<"---------------\n\n";
		cout <<"\nAnge ena sidan i triangeln: ";
		a = mataIn();
		cout <<"\nAnge hypotenusan: ";
		b = mataIn();
		if (a < 0 || b < 0)
		{
			cout <<"Otillåten inmatning !"<< endl;
			getch();
		}
		else if (a > b)
		{
			cout <<"\nHypotenusan måste vara längst !";
			getch();
		}
		else
		{
			c = sqrt (pow(b,2) - pow(a,2));
			cout <<"\nSidan är är: "<< c;
			getch();
		}
		cout <<"Tryck på någon tangent !";
		getch();
	}
}

/***************************************************************/
// Cosinussatsen
/***************************************************************/
void funk5()
{
	float a,b,c,x,y;
	int vad;

	clrscr();
	cout <<"Cosinus-satsen"<< endl;
	cout <<"--------------"<< endl;
	cout <<"Vad vill du beräkna? "<< endl;
	cout <<"1. En sida"<< endl;
	cout <<"2. En vinkel"<< endl;
	vad = mataIn();

	if (vad == 1)
	{
		clrscr();
		cout <<"Beräkning av en sida i en triangel"<< endl;
		cout <<"----------------------------------"<< endl;
		cout <<"Ange två sidor och dess"<< endl;
		cout <<"mellanliggande vinkel i grader"<< endl;
		cout <<"\nMata in första sidan: ";
		a = mataIn();
		cout <<"\nMata in andra sidan: ";
		b = mataIn();
		cout <<"\nMata in vinkeln: ";
		x = mataIn();
		if (a < 0 || b < 0 || x < 0)
		{
			cout <<"\nOtillåten inmatning !"<< endl;
			getch();
		}
		else
		{
			y = sqrt (pow (a , 2) + pow (b , 2) - (2 * a * b * cos(x*M_PI/180)));
			cout <<"\nSidan är " << y << endl;
			getch();
		}
	}
	if (vad == 2)
	{
		clrscr();
		cout <<"Beräkning av en vinkel i en triangel"<< endl;
		cout <<"----------------------------------"<< endl;
		cout <<"Ange tre sidor i en triangel."<< endl;
		cout <<"Den första skall vara motstående sida mot sökt vinkel!"<< endl;
		cout <<"\nMata in a: ";
		a = mataIn();
		cout <<"\nMata in b: ";
		b = mataIn();
		cout <<"\nMata in c: ";
		c = mataIn();
		if ((a > (b+c)) || (b > (a+c)) || (c > (b+a)))
		{
			cout <<"Otillåten inmatning !"<< endl;
			getch();
		}
		else
		{
			y = ((b * b) + (c * c) - (a * a)) / (2 * a * c);
			x = acos(y);
			cout <<"\nVinkel är " << x << " radianer eller "<< (x * (180/ (M_PI))) << " grader" << endl;
			getch();
		}
	}
	else
		cout <<"Fel val, försök igen !"<< endl;
}

/***************************************************************/
// Meny
/***************************************************************/
void meny()
{
	clrscr();
	cout <<"Välkommen till Crille's & Robin's matteprogram.\n";
	cout <<"-----------------------------------------------\n\n";
	cout <<"1. Förstagradsekvationer \n";
	cout <<"2. Andragradsekvationer \n";
	cout <<"3. Newton-Raphsons metod \n";
	cout <<"4. Pythagoras sats \n";
	cout <<"5. Cosinussatsen \n";
	cout <<"0. Avsluta \n\n\n";
	cout <<"Gör ditt val! \n";
}

/***************************************************************/
//Main
/***************************************************************/
int main()
{
	char val = 1;
	do
	{
		meny();
		cin >> val;
		switch (val)
		{
			case '1' : funk1();break;
			case '2' : funk2();break;
			case '3' : funk3();break;
			case '4' : funk4();break;
			case '5' : funk5();break;
			case '0' : cout <<"Programmet avslutat"<< endl;break;
			default: cout <<"Fel val"<< endl;
		}
	}
	while (val != '0');
	return 0;
}