操作系统要做生产者与消费者的问题!
#include<stdio.h>
#include<math.h>
int buffer[4];
int wait[100];
p()
{printf("producer==1.\n");
printf("consumer==2.\n");
printf("exit==0.\n");}
main()
{int a=1,empty=4,full=0,i=0,j=0,t=0,m,b,k=0;
clrscr();
p();
while(a!=0)
{printf("a=");
scanf("%d",&a);
switch(a)
{
case 1:
printf("the producer is  ");
scanf("%d",&m);
empty=empty-1;
if(empty<0)
{wait[t]=m;
printf("the buffer is full\n");

{printf("%d is in wait queue\n",wait[t]);}
t=(t+1) % 100;
break;}
d: buffer[i]=m;
   i=(i+1) % 4;
   full=full+1;
   if(full<=0)
     goto c;
   break;
   case 2:
     full=full-1;
     if(full<0)
     {printf("the buffer is empty\n");break;}
      else
c:    {printf("the consumer is  ");
      b=buffer[j];
      printf("%d\n",b);
      j=(j+1) % 4;
      empty=empty+1;
      if(empty<=0)
      {m=wait[k];
      k=(k+1) % 100;
      goto d;}}

      break;
   case 0:
    break;}}}