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ft_atoi.c
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ft_atoi.c
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/* ************************************************************************** */
/* */
/* ::: :::::::: */
/* ft_atoi.c :+: :+: :+: */
/* +:+ +:+ +:+ */
/* By: akyoshid <akyoshid@student.42.fr> +#+ +:+ +#+ */
/* +#+#+#+#+#+ +#+ */
/* Created: 2023/11/18 14:51:09 by akyoshid #+# #+# */
/* Updated: 2023/11/26 13:56:29 by akyoshid ### ########.fr */
/* */
/* ************************************************************************** */
// === DESCRIPTION ===
// Convert the initial portion of the string pointed to by str to int.
// It is equivalent to: (int)strtol(str, (char **)NULL, 10);
// === STRTOL DESCRIPTION===
// The strtol() function converts the string in str to a long value.
// The string may begin with some white spaces(as determined by isspace(3))
// followed by a single optional '+' or '-' sign
// Conversion will stop at the first character which is not a valid digit.
// === STRTOL RETURN VALUES ===
// Return the conversion result, unless the value would underflow or overflow.
// If no conversion could be performed, 0 is returned.
// If an overflow occurs, LONG_MAX is returned.
// If an underflow occurs, LONG_MIN is returned.
// === ISSPACE ===
// '\t', '\n', '\v', '\f', '\r', & ' ' are space!
#include "libft.h"
int ft_atoi(const char *str)
{
long num;
int sign;
while (*str == '\t' || *str == '\n' || *str == '\v'
|| *str == '\f' || *str == '\r' || *str == ' ')
str++;
sign = 1;
if (*str == '-')
sign = -1;
if (*str == '+' || *str == '-')
str++;
num = 0;
while (*str >= '0' && *str <= '9')
{
if (sign == 1
&& (num > LONG_MAX / 10 || (num == LONG_MAX / 10 && *str >= '7')))
return ((int)LONG_MAX);
if (sign == -1
&& (num > LONG_MAX / 10 || (num == LONG_MAX / 10 && *str >= '8')))
return ((int)LONG_MIN);
num = num * 10 + (*str - '0');
str++;
}
return ((int)num * sign);
}
// int main(void)
// {
// char str[] = "\t 1234abc567";
// // char str[] = "\t +4294967294abc567";
// // char str[] = "\t -9223372036854775808abc567";
// printf("%d\n", ft_atoi(str));
// printf("%d\n", atoi(str));
// return (0);
// }