#include <stdio.h> #include <stdlib.h> #include <windows.h> #define MAX_WIN 20 #define MAX_STAY 100 typedef struct customer *link; struct customer {   int stay;   link next; };  link GUY(int stay, link next) {   link c = malloc(sizeof *c);   c->stay = stay;   c->next = next;   return c; }   link win[MAX_WIN]; void morning() {   int i;   for(i = 0; i < MAX_WIN; i++)   {     win[i] = NULL;   } }   void come(int w, int stay) {   if(win[w] == NULL)   {         win[w] = GUY(stay, NULL);         win[w]->next = win[w];   }   else       win[w] = win[w]->next = GUY(stay, win[w]->next); }  void leave(int w) {   if(win[w]->next == win[w])   {     free(win[w]);     win[w] = NULL;   }   else   {     link t = win[w]->next;     win[w]->next = t->next;     free(t);   }        }   void guys() {   int i;   link t;   system("clear");   for(i = 0; i < MAX_WIN; i++, puts(" "))   {       printf("WIN%3d:_", i);       if((t = win[i]) == NULL)           continue;       for(; t->next != win[i]; t = t->next)       {         printf("%4d", t->next->stay);       }   }   Sleep(1); }    void later() {   int i;   for(guys(), i = 0; i < MAX_WIN; i++)   {       if(win[i] == NULL)         continue;     if(win[i]->next->stay > 0)         (win[i]->next->stay)--;     else         leave(i);   } }    int main() {   srand(time(NULL));   for(morning; ;later())   {     come(rand()%MAX_WIN, rand()%MAX_STAY+1);   }   return 0; }