class MyFloat
{
	private:
		enum {MAX_DIGITS = 20};
		char Number[MAX_DIGITS + 1];
		char NumberOfDigits;
	public:
		void Write();
		friend void AssignValue(MyFloat& X);
};
 
void MyFloat::Write( )
{  
	int i;
	if(!NumberOfDigits == 0)
	{   cout << "0.";
	    for(i=0; i<NumberOfDigits + 1; i++)
		   cout << int (Number[i]);
	}
	else
		cout << "0.?";
}

#include <iostream>
              #include "MyFloat.cpp"
              using namespace std;
 
              void AssignValue(MyFloat& X)
              {
                X.Number[1] = 1;
                X.Number[2] = 2;
                X.Number[3] = 3;          // run program first this way with
                X.NumberOfDigits = 3;     // these numbers then change
              }                           // X.NumberofDigits = 0, to test
                                          // "0.?", which stands for an error
 
              void main()
              {
                MyFloat X;
 
                AssignValue(X);
 
                cout << "X = ";
                X.Write();
                cout << endl << "Press Enter key to continue";
                cin.ignore();
               }

#include <iostream>
//#include "MyFloat.h"
//Normally you use headers instead of source files for includes ( atleast from what I've seen)
using namespace std;
 
 
 
//MyFloat.h
class MyFloat
{
	//classes start off private so you do not need to put private: in unless you declare public: first
		//#define MAX_DIGITS 20
		const int MAX_DIGITS = 20;
		//enum {MAX_DIGITS = 20};  I would define this with #define or you can make it a const int within your class
		int Number[MAX_DIGITS]; //start at index 0 and dont add one to max
		int NumberOfDigits;  //use ints so you do not have to put int(Number[i]) in write
	public:
		void Write();
		friend void AssignValue(MyFloat& X);
};
 
void MyFloat::Write( )
{  
	if(!NumberOfDigits == 0)
	{   
		cout << "0.";
	    for(int i = 0; i < NumberOfDigits; i++) //if you start at i = 0 then dont add 1 to number of digits
		   cout << Number[i]; //remove int if you use int type for your Number[] array
	}
	else
		cout << "0.?";
}
 
//main.cpp
void AssignValue(MyFloat& X)
{
	X.Number[0] = 1;  //arrays start at index 0
	X.Number[1] = 2;
	X.Number[2] = 3;          // run program first this way with
	X.NumberOfDigits = 3;     // these numbers then change
}                         	  // X.NumberofDigits = 0, to test
                       	  	  // "0.?", which stands for an error
 
int main() //in my compiler main has to be int not sure about yours
{
	MyFloat X;
 
	AssignValue(X);
 
	cout << "X = ";
	X.Write();
	cout << endl;
 
	system("PAUSE"); //use pause to stop the program from ending without waiting for user input
	return 0;
}