程序代码：

if(kbhit())
        {
            c1=getch();
            if(c1==27)
                break;
          
            if(c!='d' && c1=='a')
                c=c1;
            else if(c!='a' && c1=='d')
                c=c1;
            else if(c!='w' && c1=='s')
                c=c1;
            else if(c!='s' && c1=='w')
                c=c1;
        }

        pt=rear;
        while(pt!=head )
        {
            pt->x=pt->pre->x;
            pt->y=pt->pre->y;
            pt=pt->pre;
        }

        if(c=='d')
        {
            head->y+=1;
            if(head->y>=15)
                head->y-=15;
        }
        else if(c=='a')
        {
            head->y-=1;
            if(head->y<0)
                head->y+=15;
        }
        else if(c=='w')
        {
            head->x-=1;
            if(head->x<0)
                head->x+=15;
        }
        else if(c=='s')
        {
            head->x+=1;
            if(head->x>=15)
                head->x-=15;
        }

        pt=head->next;
        while(pt!=NULL)
        {
            if(head->x==pt->x && head->y==pt->y)
            {
                gameover=1;
                break;
            }
            pt=pt->next ;
        }
        if(gameover==1)
            break;
      
        system("cls");
        printf("  ───────────────\n");
        for(i=0;i<15;i++)
        {
            printf("│");
            for(j=0;j<15;j++)
            {

                flag=0;
                pt=head;
                while(pt!=NULL)
                {
                    if(i==pt->x && j==pt->y)
                    {
                        if(pt==head)
                            printf("■");
                        else
                            printf("□");
                        flag=1;
                        break;
                    }
                    pt=pt->next;
                }


                if(flag==0)
                {
                    if(i==food.x && j==food.y)
                    {
                        putchar(food.c);
                        putchar(food.c);
                        continue;
                    }
                    printf("  ");
                }
            }
            printf("│");
            putchar('\n');
        }
        printf("  ───────────────\n");
      
        _sleep(200);  
    }

    if(gameover==1)
        puts("game over!\n");

    getch();
}