Using a class instance as a class global. How?

Using Arduino Programming Questions
2

One approach is to make it a pointer, then call the constructor at runtime. For example:

#include <NewSoftSerial.h>

#include <WProgram.h>
#include <WConstants.h>
#include "Thermal.h"

Thermal::Thermal(int RX_Pin, int TX_Pin){

	_RX_Pin = RX_Pin;
	_TX_Pin = TX_Pin;
	
	_printer = new NewSoftSerial (_RX_Pin, _TX_Pin);
        _printer->begin (9600);
}

Thermal::~Thermal(){
	delete _printer;
}


// testing

// new and delete operators
void *operator new(size_t size_) { return malloc(size_); }
void* operator new(size_t size_,void *ptr_) { return ptr_; }
void operator delete(void *ptr_) { free(ptr_); }

Thermal * foo;

void setup ()
{
  foo = new Thermal (2, 3);
}

void loop () {
  foo->_printer->println ("hello, world");
}

and:

#ifndef Thermal_h
#define Thermal_h

#include <NewSoftSerial.h>
#include <WProgram.h>
#include <WConstants.h>

class Thermal{
  public:

    Thermal(int RX_Pin, int TX_Pin);  // constructor
    ~Thermal();  // destructor

    NewSoftSerial * _printer;

  private:
	int _RX_Pin;
  	int _TX_Pin;
};

#endif

I tested this and it did output data from pin 3.