ft_atoi.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_atoi.c                                          :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: smbaabu <smbaabu@student.42.fr>            +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2019/02/21 22:27:53 by smbaabu           #+#    #+#             */
/*   Updated: 2019/02/23 20:26:57 by smbaabu          ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

static int	is_space(char c)
{
	return (c == ' ' || c == '\t' || c == '\n'
		|| c == '\v' || c == '\f' || c == '\r');
}

int			ft_atoi(const char *str)
{
	int	i;
	int neg;
	int sum;

	sum = 0;
	neg = 0;
	i = 0;
	while (is_space(str[i]))
		i++;
	if (str[i] == '+' || str[i] == '-')
	{
		if (str[i] == '-')
			neg = 1;
		i++;
	}
	while (str[i] >= '0' && str[i] <= '9')
	{
		sum *= 10;
		sum += str[i] - '0';
		i++;
	}
	return (neg ? -(sum) : sum);
}