Return 如果在 C++ 中命令错误，则显示错误消息

Question

我正在做这个项目，我设置了一些我的 TelegramBot 可以执行的命令。如果编写的命令错误，我想添加一条错误消息。这是代码：

void handleNewMessages(int numNewMessages){

 Serial.print("Handle New Messages: ");

    Serial.println(numNewMessages);

     for (int i = 0; i < numNewMessages; i++){

// Chat id of the requester

String chat_id = String(bot.messages[i].chat_id);

if (chat_id != chatId){
  bot.sendMessage(chat_id, "Unauthorized user", "");
  continue;
}

// Print the received message
String text = bot.messages[i].text;
Serial.println(text);

String fromName = bot.messages[i].from_name;

if (text == "/FlashOn") {
  flashState = HIGH;
  digitalWrite(LED, flashState);
}

if (text == "/FlashOff") {
  flashState = LOW;
  digitalWrite(LED, flashState);
}

if (text == "/photo") {
  sendPhoto = true;
  Serial.println("New photo request");
}

if (text == "/PIRON"){
  PirControler = 1;
  bot.sendMessage(chatId, "PIR Sensor is ON, you will get a notification if a motion is detected.", "");
}

if (text == "/PIROFF"){
  PirControler = 0;
  bot.sendMessage(chatId, "PIR sensor is OFF, you will no longer receive any notification.", "");

if (text == "/start"){
  String welcome = "Hi sir, here are the commands I can execute for you :\n";
  welcome += "/Photo : Take a new photo.\n";
  welcome += "/FlashOn : Turns LED On.\n";
  welcome += "/FlashOff : Turns LED off\n";
  welcome += "/PIRON : Activate your PIR sensor.\n";
  welcome += "/PIROFF : Shut your PIR sensor down.\n";
  // welcome += "/readings : request sensor readings\n\n";
  welcome += "You'll receive a photo whenever motion is detected.\n";
  bot.sendMessage(chatId, welcome, "Markdown");
}
/*else {
  bot.sendMessage(chatId, "I don't understand, sorry. Refer to the commands I showed you above.", "");      
} **(Here is the message that I'd like to add)**
}
}

但是，通过尝试添加最后一行，

/*else {
  bot.sendMessage(chatId, "I don't understand, sorry. Refer to the commands I showed you above.", "");      
}*/

它 returns 除了“/start”命令之外的所有正确命令都是错误的。

任何关于我如何做到这一点的想法将不胜感激:)

Answer 1

让我们缩小示例

if (text == "/FlashOn") {
  do stuff
}

if (text == "/start"){
  do stuff
}
else {
  report error
}

此代码将始终测试 if (text == "/start")，而不管 if (text == "/FlashOn") 的结果如何，如果 text 是“/FlashOn”，则它不能是“/start”并将执行 else 并打印错误信息。

解决方案

if (text == "/FlashOn") {
  do stuff
}

else if (text == "/start"){
  do stuff
}
else {
  report error
}

现在 if (text == "/start") 将不会被测试并且 else 案例将不会运行 if text == "/FlashOn".

如果完全缩进和括起来会是什么样子：

if (text == "/FlashOn") {
  do stuff
}
else {
  if (text == "/start"){
    do stuff
  }
  else {
    report error
  } 
}

Return 如果在 C++ 中命令错误，则显示错误消息

Return error message if the command is wrong in C++

c++

arduino