adventofcode

day1.c (937B)

#include <assert.h> /* assert() */
#include <fenv.h>   /* fesetround(), FE_DOWNWARD */
#include <math.h>   /* lround() */
#include <stdio.h>  /* printf(), getline() */
#include <stdlib.h> /* atol() */
long int
fuel_required(long int mass)
{
	long int result;
	fesetround(FE_DOWNWARD);
	result = (lround(mass / 3) - 2);
	return result;
}
long int
fuel_fuel(long int input)
{
	long int result;
	result = fuel_required(input);
	if(result <= 0)
		return 0;
	else
		return result + fuel_fuel(result);
}
int
main(void)
{
	char *line_mass        = NULL;
	size_t len             = 0;
	long int modules_total = 0, grand_total = 0, module_fuel;
	while(getline(&line_mass, &len, stdin) != -1)
	{
		module_fuel = fuel_required(atol(line_mass));
		modules_total += module_fuel;
		grand_total += module_fuel + fuel_fuel(module_fuel);
	}
	printf("Modules fuel: %ld\n", modules_total);
	printf("Grand total: %ld\n", grand_total);
	return 0;
}