ft_itoa.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_itoa.c                                          :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: aalvarez <aalvarez@student.42.fr>          +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2022/08/17 18:30:13 by aalvarez          #+#    #+#             */
/*   Updated: 2022/08/17 19:58:11 by aalvarez         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "libft.h"
#include <stdlib.h>

/**
 * @brief calculates the size of the allocation
 * needed for the string.
 * 
 * @param n integer to be representd as a string.
 * @return int the size needed to the allocation,
 * this funtion does not count the NULL terminating
 * byte.
 */
static int	ft_arrsize(int n)
{
	int	size;

	size = 0;
	if (n <= 0)
		size++;
	while (n)
	{
		size++;
		n /= 10;
	}
	return (size);
}

/**
 * @brief converts the integer
 * n to its string representation.
 * 
 * @param n integer to be represented as a string.
 * @return char* result of the string representation of n.
 */
char	*ft_itoa(int n)
{
	char	*result;
	int		size;
	long	nbr;

	size = ft_arrsize(n);
	nbr = n;
	result = (char *) malloc(sizeof(char) * (size + 1));
	if (!result)
		return (NULL);
	if (nbr < 0)
	{
		result[0] = '-';
		nbr *= -1;
	}
	if (!nbr)
		result[0] = '0';
	result[size--] = 0;
	while (nbr)
	{
		result[size--] = (nbr % 10) + '0';
		nbr /= 10;
	}
	return (result);
}