c03 and begin c04

1 files changed, 50 insertions, 0 deletions

diff --git a/c04/ex03/ft_atoi.c b/c04/ex03/ft_atoi.c
new file mode 100644
index 0000000..0d4247b
--- /dev/null
+++ b/c04/ex03/ft_atoi.c
@@ -0,0 +1,50 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_atoi.c                                          :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: cacharle <charles.cabergs@gmail.com>       +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2019/07/06 07:31:38 by cacharle          #+#    #+#             */
+/*   Updated: 2019/07/06 08:36:47 by cacharle         ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+int	pow10(int exponent)
+{
+	int	accumulator;
+
+	accumulator = 1;
+	while (exponent > 0)
+	{
+		accumulator *= 10;
+		exponent--;
+	}
+	return (accumulator);
+}
+
+int	ft_atoi(char *str)
+{
+	int	is_negative;
+	int	nb;
+	int	i;
+
+	while (*str == ' ' || *str == '\t' || *str == '\n'
+		   || *str == '\v' || *str == '\f' || *str == '\r')
+		str++;
+	while (*str == '-' || *str == '+')
+	{
+		if (*str == '-')
+			is_negative = !is_negative;
+		str++;
+	}
+	i = 0;
+	while (str[i] >= '0' && str[i] <= '9')
+	{
+		nb += pow10(i) * (str[i] - '0');
+		i++;
+	}
+	if (is_negative)
+		nb = -nb;
+	return (nb);
+}