Need Help In classes

Projects Programming
1

Hello.

I was trying to understand the code of online tutorials, but I got stuck at the class parts. So, it will be great if someone helps me on this.

enum speedSettings 
{
  SLOW = 190,
  NORMAL = 225,
  FAST=255
};

class Car 
{
  private:
  //motor 1 connections
  int in1 = 16;
  int in2 = 17;
  //motor 2 connections
  int in3 = 32;
  int in4 = 33;

  const int SPEED_CONTROL_PIN_1 = 21;
  const int SPEED_CONTROL_PIN_2 = 22;

  const int freq  = 3000;
  const int channel_0 = 0;
  const int channel_1 = 1;
  const int resolution = 8;

  speedSettings currentSpeedSettings;

  public:
  Car() 
  {
    pinMode(in1, OUTPUT);
    pinMode(in2, OUTPUT);
    pinMode(in3, OUTPUT);
    pinMode(in4, OUTPUT);
    pinMode(SPEED_CONTROL_PIN_1, OUTPUT);
    pinMode(SPEED_CONTROL_PIN_2, OUTPUT);


    digitalWrite(in1, LOW);
    digitalWrite(in2, LOW);
    digitalWrite(in3, LOW);
    digitalWrite(in4, LOW);

    ledcAttachPin(SPEED_CONTROL_PIN_1, channel_0);
    ledcAttachPin(SPEED_CONTROL_PIN_2, channel_1);


    ledcSetup(channel_0, freq, resolution);
    ledcSetup(channel_1, freq, resolution);

    // initialize default speed to SLOW

    //PENDING


  };
  void setCurrentSpeed(speedSettings newSpeedSettings)
    {
      Serial.println("car is changing speed...");
      currentSpeedSettings = newSpeedSettings;
    }





};

So, as far as I can tell, he created a new variable here called currentSpeedSettings.

  speedSettings currentSpeedSettings;

Before going forward the enum stores value as int

SLOW = 190,
  NORMAL = 225,
  FAST=255

But this function inside class

void setCurrentSpeed(speedSettings newSpeedSettings)
    {
      Serial.println("car is changing speed...");
      currentSpeedSettings = newSpeedSettings;
    }

I am not able to understand the function parameter

setCurrentSpeed(speedSettings newSpeedSettings)

So later in the code they have used this function like this

setCurrentSpeed(speedSettings::NORMAL);

So speedSettings is the enum and another parameter is newSpeedSettings, so basically I am not getting these two.

2

You are almost there - newSpeedSettings is a parameter of type speedSettings (like a typical function).

The line

is passing the enum value NORMAL. The :: is a scope resolution operator essentially telling the compiler that NORMAL in defined in the enum speedSettings.

3

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