ft_atoi.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_atoi.c                                          :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: elel-yak <elel-yak@student.1337.ma>        +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2022/10/08 15:12:06 by elel-yak          #+#    #+#             */
/*   Updated: 2022/10/25 23:40:46 by elel-yak         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "libft.h"

int	ft_atoi(const char *str)
{
	int				i;
	int				ich;
	unsigned long	res;

	i = 0;
	ich = 1;
	res = 0;
	while ((str[i] >= 9 && str[i] <= 13) || str[i] == 32)
		i++;
	if (str[i] == '+' || str[i] == '-')
	{
		if (str[i] == '-')
			ich = -ich;
		i++;
	}
	while (str[i] >= '0' && str[i] <= '9')
	{
		res = res * 10 + str[i++] - 48;
		if (res > __LONG_MAX__)
			return (0 - (ich == 1));
	}
	return (ich * res);
}