// This program lets the user enter a number. The
// dollarFormat function formats the number as
// a dollar amount.
#include <iostream>
#include <string>
using namespace std;

// Function prototype
void dollarFormat(string &);

int main ()
{
   string input;

   // Get the dollar amount from the user.
   cout << "Enter a dollar amount in the form nnnnn.nn : ";
   cin >> input;
   dollarFormat(input);
   cout << "Here is the amount formatted:\n";
   cout << input << endl;
   return 0;
}

//************************************************************
// Definition of the dollarFormat function. This function    *
// accepts a string reference object, which is assumed to    *
// to hold a number with a decimal point. The function       *
// formats the number as a dollar amount with commas and     *
// a $ symbol.                                               *
//************************************************************

void dollarFormat(string &currency)
{
   int dp;

   dp = currency.find('.');   // Find decimal point
   if (dp > 3)                // Insert commas
   {
      for (int x = dp - 3; x > 0; x -= 3)
         currency.insert(x, ",");
   }
   currency.insert(0, "$");   // Insert dollar sign
}