Functions

Reference Parameters

The parameter variables we have looked at so far are called value parameters.
Value parameters are separate variables from the ones in main() (or another calling function).
Modification of value parameters does not affect the original value.
A reference parameter does not create a new variable, but refer to an existing variable.
Any change in a reference parameter is actually a change in the variable to which it refers.

Reference parameters are indicated using an & between the parameter's type and name.

void raise_salary(Employee& e, double by)
{
   double new_salary = e.get_salary() * ( 1 + by / 100);
   e.set_salary(new_salary);
}