$//$ Member function to calculate payroll

double calculatePayroll$()$ const $\{$

double payroll $=$ grossSales $*$ commissionRate;

$//$ Add $$100\mathrm{.}00$ if it's the employee's birthday month

if $($isBirthdayMonth$())\{$

payroll $+=100\mathrm{.}0$;

cout $<<$ "Birthday bonus of $$100\mathrm{.}00$ added to the payroll!" $<<$ endl;

$\}$

return payroll;

$\}$