Currency Conversion using OO

[Willing 2 Learn]

I'm still having trouble getting my program to do arithmetic in
cents(keeping all #'s) then convert the answer in a format of dollars &

cents. The main program should add, subtract, scalar multiply(by int)&

show, have a constructor w/ & w/out arguments. Header file should have
private data & all 6 functions from above.Class definition file should
implement my ADT class.
What I have so far:
Main program
#include "jahcurrency.h"
#include <iostream.h>
void main()
{
Currency a(4,3);
Currency b(2,1);
Currency total;


total=a.add(b);
total.show();
total=a.sub(b);
total.show();
total=a.multiply(5);
total.show();


}


Header file
class Currency
{
private:
double cents;
public:
Currency();
Currency(int d,int c);
Currency add(Currency b);
Currency sub(Currency b);
Currency multiply(double d);
double calc(Currency s);
double calc2(Currency f);
void show(void);

};


Class definition
#include "jahcurrency.h"
#include <iomanip.h>
#include <math.h>
#include <iostream.h>

char sign='$';


Currency::Currency()
{
x=0;



}


Currency::calc2(Currency f)
{

f=(x*100)-(x%100);


return f;


}


Currency::calc(Currency s)
{

s=(x%100);


return s;



}


Currency::Currency(int d, int c)
{

d=(x*100)-(x%100);
c=(x%100);


return d;



}


Currency::add(Currency b)
{
Currency x;
x.cents= x+ b.x;

return x;


}


Currency::sub(Currency b)
{
Currency x;
x.cents= x- b.x;

return x;


}


Currency::multiply(Currency d)
{
Currency x;
x.cents= x*d.x;

return x;



}


Currency::show()
{
cout<<sign<<d<<". "<<s<<endl;

}


How different would the program be if cents is in long then convert
ans. for each opeartion to dollars & cents ?
Your help would be appreciated in how to fix this problem.