:OOOOOOO

include <stdio.h>
#include <stdlib.h>

double OA4(const char *filename)
{
	int pole[100], i=0, sum=0;
	double priemer=0;
	FILE *f;
	f=fopen(filename,"r");
	if(f==NULL){
		printf("Error\n");
		exit(-1);
	}
	while((fscanf(f,"%i",&pole[i]))==1){
		sum+=pole[i];
		i++;
	}
	fclose(f);
	priemer= (double) sum/i;
	return priemer;
}

int main()
{
	printf("%.2lf\n",OA4("cisla.txt"));
	return 0;
}