Added code to deal with improperly formatted codes

includes/connect-helpers.hpp

@@ -63,6 +63,9 @@ namespace connect_code {
 
 	/* Given a code, decode it and return a vector with the address and port */
 	std::vector<std::string> decode(std::string connect_code) {
+		if (connect_code.find("_") == std::string::npos) {
+			throw std::invalid_argument("Invalid code entered.");
+		}
 		std::vector<std::string> result = tokenize_str(connect_code, "_"); /* Split the string into address and port */
 		std::string address = result[0]; /* Address (in base 16) */
 		std::string port = result[1]; /* Port (in base 16) */
@@ -80,5 +83,4 @@ namespace connect_code {
 		return ret_val;
 	}
 
-	
 }