Functions

Parameters

When a function starts, its parameter variables are initialized with the expressions in the function call.
```
b = future_value(total / 2, rate, year2 - year1);
```

It is entirely legal to modify the values of the parameter variables later.

double future_value(double, initial_balance, double p, int n)
{
   p = 1 + p / 100;
   double b = initial_balance * pow(p, n);
   return b;
}