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ft_itoa.c
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ft_itoa.c
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/* ************************************************************************** */
/* */
/* ::: :::::::: */
/* ft_itoa.c :+: :+: :+: */
/* +:+ +:+ +:+ */
/* By: kalmheir <[email protected] +#+ +:+ +#+ */
/* +#+#+#+#+#+ +#+ */
/* Created: 2021/10/03 14:34:32 by kalmheir #+# #+# */
/* Updated: 2021/10/06 13:30:53 by kalmheir ### ########.fr */
/* */
/* ************************************************************************** */
#include "libft.h"
static int ft_pow(int nb, int power)
{
if (power < 0)
return (0);
if (power == 0)
return (1);
return (nb * ft_pow(nb, power - 1));
}
static char fast_log10(int n)
{
if (n == (int)0x80000000)
return (10);
if (n < 0)
n = -n;
if (n <= 9)
return (1);
if (n <= 99)
return (2);
if (n <= 999)
return (3);
if (n <= 9999)
return (4);
if (n <= 99999)
return (5);
if (n <= 999999)
return (6);
if (n <= 9999999)
return (7);
if (n <= 99999999)
return (8);
if (n <= 999999999)
return (9);
return (10);
}
char *ft_itoa(int n)
{
char *result;
int digits;
int neg;
int i;
i = 0;
digits = fast_log10(n);
neg = n < 0;
result = malloc(neg + digits + 1);
if (!result)
return (0);
if (neg)
result[i++] = '-';
result[digits + neg] = 0;
if (neg)
neg = -1;
else
neg = 1;
while (digits)
result[i++] = (neg * ((n / ft_pow(10, --digits)) % 10)) + '0';
return (result);
}