42_push_swap/ft_isnum.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_isnum.c                                         :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: cchauvet <cchauvet@student.42angouleme.fr  +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2022/11/08 18:43:06 by cchauvet          #+#    #+#             */
/*   Updated: 2022/12/11 17:49:49 by cchauvet         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "pushswap.h"

int	ft_isnum(char *str)
{
	long int	i;
	int			sign;

	sign = 1;
	if (*str == '-')
		sign = -1;
	i = 0;
	if (*str == '-' || *str == '+')
		str++;
	if (*str == '\0')
		return (0);
	while (*str != '\0')
	{
		if (i * sign > INT_MAX || INT_MIN > i * sign)
			return (0);
		if (!(*str >= '0' && *str <= '9'))
			return (0);
		i = i * 10 + *str - '0';
		str++;
	}
	return (1);
}