#include <stdio.h>
#include <conio.h>
#include <math.h>

#define PI 3.1416


int calcNEntiers( int n )
{
	int S = 0;
	for( int i = 1; i <= n ; i ++ )
	{
		S = S + i;
	}
	return S;
}

int calcNEntiersRecurs( int n )
{
	if( n == 0 ) return 0;
	return n + calcNEntiersRecurs( n - 1 );
}

int calcNFact( int n )
{
	int Fact = 1;
	for( int i = 1; i <= n ; i ++ )
	{
		Fact = Fact * i;
	}
	return Fact;
}

int calcNFactRecurs( int n )
{
	if( n == 0 ) return 1;
	return n * calcNFactRecurs( n - 1 );
}

double calcPuis( double x, double n )
{
	if( x < 0 ) return -1;
	return exp( n * log(x) );
}

double calcPuis2( double x, int n )
{
	if( n == 0 ) return 1;
	return calcPuis2( x, n - 1 )  * x;
	// Rq formule x(n+1) / x impossible car pas
	// de condition d'arret
}


double calcLogbase( double x, double base )
{
	return log(x) / log(base);
}


double radian2degre( double rad )
{
	return (rad * 180 / PI);
}

double degre2radian( double deg )
{
	return (deg * PI) / 180;
}

void main()
{
	int r1, r2, n;
	double dx, dn, dr1, dr2; float saisiescanf;

	// menage ecran
	clrscr();
	fflush(stdin);

	// calcul de n entiers
	printf( "\nSomme de n entier (saisir n): " );
	scanf( "%d", &n );
	r1 = calcNEntiers( n );
	r2 = calcNEntiersRecurs( n );
	printf( "\nResultat 1->%d, 2->%d\n", r1, r2 );

	// Factoriel
	printf( "\nFactoriel n (saisir n): " );
	scanf( "%d", &n );
	r1 = calcNFact( n );
	r2 = calcNFactRecurs( n );
	printf( "\nResultat 1->%d, 2->%d\n", r1, r2 );

	// Puissance
	printf( "\nFactorielpuissance X^N (saisir x puis n): " );
	scanf( "%f", &saisiescanf );
	dx = saisiescanf;
	scanf( "%f", &saisiescanf );
	dn = saisiescanf;
	dr1 = calcPuis( dx, dn );
	dr2 = calcPuis2( dx, (int)dn );
	printf( "\nResultat 1->%f, 2->%f\n", (float)dr1, (float)dr2 );

	// log
	printf( "\nLog10(10) = %f\n", (float)calcLogbase( 10, 10 ) );
	printf( "\nradian2degre(2PI)=%f\n", (float)radian2degre( 2 * PI ) );
	printf( "\ndegre2radian(360)=%f\n", (float)degre2radian(360) );

	getch();
}