ft_atoi.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_atoi.c                                          :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: apuchill <apuchill@student.42sp.org.br>    +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2019/12/13 14:41:25 by exam              #+#    #+#             */
/*   Updated: 2020/11/05 13:39:09 by apuchill         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

/*
** LIBRARY: <stdlib.h>
** SYNOPSIS: convert ASCII string to integer
**
** DESCRIPTION:
** 		The atoi() function converts the initial portion of the string pointed
**	to by str to int representation.
*/

int		ft_atoi(const char *str)
{
	int	i;
	int	s;
	int	res;

	i = 0;
	s = 1;
	res = 0;
	while (str[i] == ' ' || str[i] == '\n' || str[i] == '\t' ||
			str[i] == '\v' || str[i] == '\f' || str[i] == '\r')
		i++;
	if (str[i] == '-' || str[i] == '+')
	{
		if (str[i] == '-')
			s = -1;
		i++;
	}
	while (str[i] >= '0' && str[i] <= '9')
	{
		res = (res * 10) + (str[i] - '0');
		i++;
	}
	return (res * s);
}