#include <stdio.h>
#include <stdlib.h>
// #include <unistd.h>
// #include <assert.h>

double sin(double x){
	int sign = 1;
	int i;
	int exp = 1;
	double sum = 0;
	for(i = 0; i < 5; i++){
		//printf(" %i (%f)^%i / %i\n", sign, x, exp, fak(exp));
		sum += sign * pwr(x,exp) / fak(exp);
		exp = exp + 2;
		sign = -sign;
	}
	return sum;
}

double pwr(double x, int y){
	int i;
	double result = 1;
	for(i = 0; i < y; i++){
		result = result * x;
	}
	return result;
}

int fak(int n){
	int result = 1;
	while(n > 1){
		result *= n;
		n--;
	}
	return result;
}

int main(void){
	int f = fak(3);
	int p = pwr(3,3);
	double s = sin(3.141592653);
	printf("fak: %i\n", f);
	printf("pow: %i\n", p);
	printf("Sinus: %f\n", s);
	return 0;
}