Define n=5;
Semaphore mutex=1;
Semaphore customers=0;
Semaphore barbers=1;
Int waiting=0; //等候理发的顾客数


Void baber()
{
While(true
{
Wait(customers));//若无顾客，理发师睡眠
Wait(mutex);
Waiting- -;
Signal(mutex);
Signal(barbar);
}

Void customer()
{
wait(mutex);
If(waiting<n)
{
Waiting++；
Signal(mutex);
Signal(customers);//如果理发师睡觉，叫醒理发师
Wait(barber)；//理发师在理发，顾客等候；
}
Else
Signal(mutex);//