/* a vizsgált függvény az x^3 + 1*/
double fgv(double x){
	return (x*x*x+1);	/* pow(x,3) + 1;*/
};

int trapez(double a, double b, int n, double *eredmeny)
{
	double sum, l;		

	l = (b-a)/n;		
	sum = 0;					

	for (int i=0; i < n; i++)
	{
	
		sum += ( (fgv(a + l*i) + fgv(a + l*(i+1)) ) /2) * l;	
									
	}

	*eredmeny = sum;
	return 0;				
}