C++ struct Updates balance in a structure

#include <iostream>
using namespace std;
#include <iomanip.h>
struct customer_rec
{
   char cust_name[25];
   double balance;
   float dis_rate;
} ;/*from  www .  j  a  v a 2 s  .com*/
void main()
{
   struct customer_rec customer = {"Steve Thompson", 431.23, .25};
   cout << "Before the update, " << customer.cust_name;
   cout << " has a balance of $" << setprecision(2) << customer.balance << "\n";

   customer.balance *= (1.0-customer.dis_rate);
   cout << "After the update, " << customer.cust_name;
   cout << " has a balance of $" << customer.balance << "\n";
   return;
}