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ft_atoi.c
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ft_atoi.c
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/* ************************************************************************** */
/* */
/* ::: :::::::: */
/* ft_atoi.c :+: :+: :+: */
/* +:+ +:+ +:+ */
/* By: dalves-p <dalves-p@student.42sp.org.br> +#+ +:+ +#+ */
/* +#+#+#+#+#+ +#+ */
/* Created: 2021/05/25 15:58:20 by dalves-p #+# #+# */
/* Updated: 2021/06/26 16:55:50 by dalves-p ### ########.fr */
/* */
/* ************************************************************************** */
#include "libft.h"
/*
** LIBRARY: <stdlib.h>
** DESCRIPTION:
** The atoi() function converts the initial portion of the string pointed
** to by str into integer.
** Discards whitespace characters (' ' , '\r', '\n', '\f', '\v', '\t') from
** the beginning of the string
** Accepts the optional "+" or "-" sign at the beggining of the string.
** Ignores additional non-numerich characters.
** Returns 0 for invalid number or no numeric string.
*/
int ft_atoi(const char *str)
{
unsigned int i;
int sign;
unsigned int result;
i = 0;
sign = 1;
result = 0;
if (str[i] == '0' && str[i + 1] == '\0')
return (0);
while (str[i] == ' ' || str[i] == '\f' || str[i] == '\n'
|| str[i] == '\r' || str[i] == '\t' || str[i] == '\v'
|| str[i] == '0')
i++;
if (str[i] == '-' || str[i] == '+')
{
if (str[i] == '-')
sign = -1;
i++;
}
while ((str[i] >= '0' && str[i] <= '9') && (str[i] != '\0'))
{
result = (result * 10) + (str[i] - '0');
i++;
}
return (sign * result);
}