first commit of v2 ft_printf

42-libft/ft_itoa.c

@@ -0,0 +1,62 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_itoa.c                                          :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: dgaillet <dgaillet@student.42.fr>          +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2025/11/07 13:06:35 by dgaillet          #+#    #+#             */
+/*   Updated: 2025/11/12 14:20:16 by dgaillet         ###   ########lyon.fr   */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "libft.h"
+
+static size_t	count_digits(int n)
+{
+	size_t	size;
+
+	size = 0;
+	if (n <= 0)
+		size++;
+	while (n)
+	{
+		n /= 10;
+		size++;
+	}
+	return (size);
+}
+
+static void	insert_char(char *str, unsigned int nbr, size_t index)
+{
+	while (nbr)
+	{
+		str[index--] = nbr % 10 + '0';
+		nbr /= 10;
+	}
+}
+
+char	*ft_itoa(int n)
+{
+	unsigned int	nbr;
+	char			*str;
+	size_t			size;
+
+	nbr = n;
+	if (n < 0)
+		nbr = n * -1;
+	size = count_digits(n);
+	str = malloc(sizeof(char) * (size + 1));
+	if (!str)
+		return (NULL);
+	str[size] = '\0';
+	if (nbr == 0)
+		str[0] = '0';
+	else
+	{
+		if (n < 0)
+			str[0] = '-';
+		insert_char(str, nbr, size - 1);
+	}
+	return (str);
+}