Comparing custom variable type definitions

Question

In a library I am using with an OBD adapter, they define a public function to get the state of the OBD connection using some strange (and, in my opinion, useless) custom defined variable type:

// states
typedef enum {
 OBD_DISCONNECTED = 0,
 OBD_CONNECTING = 1,
 OBD_CONNECTED = 2,
 OBD_FAILED = 3
} OBD_STATES;
...
// get connection state
virtual OBD_STATES getState() { 
 return m_state; 
}

How can I get the state into a variable such as boolean isConnected or int state so it can interact with the rest of my code? I have tried the following with no luck:

boolean isConnected = obd.getState() == OBD_CONNECTED;
if(isConnected) { ... }
int state = (int) obd.getState();
if(state == 2) { ...}

Answer 1

In response to your answer: why don't you think it is convenient? As you already noticed, you can use the enum values directly in your sketch.

Anyway, it is better to use a switch statement:

Serial.write("ODB State: ");
switch (odb.getState()) {
 case ODB_DISCONNECTED: 
 Serial.write("Disconnected");
 break;
 case OBD_CONNECTING:
 Serial.write("Connecting");
 break;
 case OBD_CONNECTED:
 Serial.write("Connected");
 break;
 case OBD_FAILED:
 Serial.write("Failed");
 break;
 default:
 // Error case
 break;
}
Serial.write("\n");

This way, whenever the enum is changed (e.g. added items), you automatically fall into the error state, so you know you have to adapter the code.

• Benjamin Brownlee: I realize now it is actually pretty convenient. I was just used to java where I typically return some sort of integer and then provide static constants from the constructor class to compare it against.
• Juraj: Java has enum type too

Answer 2

I found the answer to my problem, but it is not very convenient.

Serial.write("ODB State: ");
OBD_STATES state = obd.getState();
if(state == OBD_DISCONNECTED) Serial.write("Disconnected");
if(state == OBD_CONNECTING) Serial.write("Connecting");
if(state == OBD_CONNECTED) Serial.write("Connected");
if(state == OBD_FAILED) Serial.write("Failed");
Serial.write("\n");