/* 6-2
 * Tanel Toova
 * faktoriaali arvutamine rekursiivse funktsiooniga
 */
#include <stdio.h>

int ftr;

int faktoriaal(int arv)
{	//if arv is greater than 0 then the variable ftr must be multiplicated with it one more time 
	if(arv>0){
		ftr=ftr*arv; //NB! first time ftr is 1 
		faktoriaal(arv-1); //function faktoriaal is called out with parameter arv that decreases by 1 every time
	}
	return(ftr); //value of ftr is returned
}

int main(int argc, char **argv)
{	//if argument is missing or has impropper value
	if(argc!=2 || atoi(argv[1])<1 || atoi(argv[1])>10){
		printf(" Usage: %s <integer 1-10> \n",argv[0]);
		exit(1);
	}

	ftr=1;
	faktoriaal(atoi(argv[1]));
	printf("Faktoriaal arvust %s on %i\n",argv[1],ftr);
	return(0);	
}