feat(09): start the parsing of the input

cpp09/ex01/main.cpp

@@ -6,10 +6,35 @@
 /*   By: rparodi <rparodi@student.42.fr>            +#+  +:+       +#+        */
 /*                                                +#+#+#+#+#+   +#+           */
 /*   Created: 2025/04/27 12:58:08 by rparodi           #+#    #+#             */
-/*   Updated: 2025/04/27 13:00:01 by rparodi          ###   ########.fr       */
+/*   Updated: 2025/04/27 15:50:20 by rparodi          ###   ########.fr       */
 /*                                                                            */
 /* ************************************************************************** */
 
-int main(int argc, char **argv) {
+#include <iostream>
+#include <stack>
+#include "RPN.hpp"
 
+/**
+ * @brief check if the input have only numbers and operators
+ *
+ * @param str the input of the user
+ * @return true if the input is valid, false otherwise
+ */
+bool check_input(std::string str) {
+	std::string allowed = "0123456789 +-*/";
+	for (std::string::const_iterator it = str.begin(); it != str.end(); ++it) {
+		if (allowed.find(*it) == std::string::npos)
+			return false;
+	}
+	return true;
+}
+
+int main(int argc, char **argv) {
+	if (argc != 2) {
+		std::cerr << CLR_RED << "Usage:\t" << argv[0] << " <string>" << CLR_RESET << std::endl;
+	}
+	std::string input = argv[1];
+	if (!check_input(input)) {
+		std::cerr << CLR_RED << "Error:\tYour input can only have digits, spaces and the operators '+' '-' '*' '/'" << CLR_RESET << std::endl;
+	}
 }