do{
flag[i] = true;
turn = j;
while(flag[j] && turn == j);
//
//臨界區
//
flag[i] = false;
//
//剩餘區
//
}while(true)
 

bool TestAndSet(bool *target){
        bool rv = *target;
        *target = true;
         return rv;
}

do{
while(TestAndSet(&lock))
;//do nothing
//
//臨界區
//
lock = false;
}while(true)
 

void Swap(bool *a, bool *b)
{
bool temp = *a;
*a = *b;
*b = temp;
}

do{
key = true;
while(key == true)
         Swap(&lock, &key);
//
//臨界區
//
lock = false;
}while(true)

do{
waiting[i] = true
key = true;
while(waiting[i] && key)
         key = TestAndSet(&lock);

waiting[i] = false;
//
//臨界區
//
j = (i + 1)%n;
while((j != 1) && !waiting[j])
        j = (j + 1)%n;

if(j == i)
       lock = false;
else
        waiting[j] = false;
}while(true)

wait(s)
{
    while(s <= 0)
                 ;//do nothing
      s--;
}

signal(s)
{
       s++;
}