Shared data:

var customers: semaphore; // # of customers waiting for service
var barbers: semaphore; // # of barbers waiting for customers 
var mutex: semaphore; // for mutual exclusion 
var waiting: int; // customers waiting (not being cut) 
var chairs: int; // # of chairs for waiting 

customers:= 0; 
barbers:= 0; 
mutex:= 1; 
waiting:= 0; 
chairs:= 5; 


Barber:

repeat
    waiting:= waiting - 1; // decrement count of waiting customers
    cut_hair(); // cut the customer's hair
until false; 


Customer:

if (waiting < chairs)
    then begin 
        waiting:= waiting + 1;
        get_haircut(); // get a haircut
    end
    else