Modify the Following Class Definition So That It Uses the #Ifndef

Essay

Modify the following class definition so that it uses the #ifndef , #define and #endif directives:
class Salesperson
{
private:
int idNum;
string name;
public:
Salesperson(int, string);
void display();
};
Salesperson::Salesperson(int id, string lastName)
{
idNum = id;
name = lastName;
}
void Salesperson::display()
{
cout