4. C++ syntax question - Defining an object in a class that requires arguments?

C++ syntax question - Defining an object in a class that requires arguments?


  • I need some help with how to properly define an object in a class as a public object of the class for objects that require arguments. I would like to hardcode the arguments. For example I want to make the second UART port in a class and hardcode the UART to 2.

    .h file for class

    #ifndef TestClass_h
#define TestClass_h

#include "Arduino.h"
#include <M5Unified.h>

class TestClass {
  public:
    //-- Define RS458 to UART to UART2, HardwareSerial needs a UART number passed to it --

    //What I have tried, I would like to hardcode the UART number to 2. How do I do this?????
    HardwareSerial SerialRS485; // 1 - Does not compile, I need something in the .cpp file to make this work
    HardwareSerial SerialRS485(uint8_t _uart); // 2 - Can get this to compile but then does not compile if I use a uncomment the test funciton
    HardwareSerial SerialRS485(uint8_t 2); // 3 - Does not compile

    //constructor
    TestClass();
      
    //Functions - Main
    void testFunction();


  private:
    uint16_t _private1 = 0;

};

#endif

    .cpp file for class

    #include "TestClass.h"
#include "Arduino.h"

//Constructor def
TestClass::TestClass() {
}

void TestClass::testFunction() {
    Serial.println("USB Serial Port");
    SerialRS485.println("RS485 Serial Port");
}

    main ino file

    #include "Arduino.h"
#include <M5Unified.h> //For M5Stack ESP Hardware

//Create test class
#include "TestClass.h"
TestClass TestObject;

void setup(void)
{
  auto cfg = M5.config();  //M5 Unified config
  M5.begin(cfg);
  delay(500);
}

void loop(void)
{
  M5.update(); //Update button state
  TestObject.testFunction();
  delay(1000);
}
    0
    P
     1 Reply
  • P

    @lukes said in C++ syntax question - Defining an object in a class that requires arguments?:

    HardwareSerial

    Maybe this solves your problem ...

    class StaticClass {
private:
    int myContent;
public:
    StaticClass(int v){myContent = v;}

    void printout(){printf("%d\n",myContent);}
};
    

class TestClass {

public:
    //StaticClass myClass = StaticClass(42);    // With C11
    StaticClass myClass;
        
    TestClass() : myClass(42)
    {
    }
        
    void doit()
    {
        myClass.printout();
    }
};


int main(void)
{
    TestClass tc;
    
    tc.doit();
}
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