Simula I

BEGIN
   COMMENT Simple queuing system simulation;
   INTEGER customers, served;
   REAL arrival_time, service_time, total_wait;
   
   customers := 0;
   served := 0;
   total_wait := 0.0;
   
   arrival_time := 0.0;
   service_time := 5.0;
   
   WHILE arrival_time < 100.0 DO
   BEGIN
      customers := customers + 1;
      total_wait := total_wait + (service_time * served);
      arrival_time := arrival_time + 10.0;
      
      IF customers > 0 THEN
      BEGIN
         customers := customers - 1;
         served := served + 1;
      END;
   END;
   
   OUTTEXT("Total customers served: ");
   OUTINT(served, 5);
   OUTIMAGE;
   OUTTEXT("Average wait time: ");
   OUTFIX(total_wait / served, 3, 10);
   OUTIMAGE;
END