최적화하면 할 곳이 더 많지만, 귀찮아서 대강 이것만...

int frame=0;
void animate_self() // 애니메이션 함수
{
                if(++flag>=5)
                {
                        if(++frame>=4)frame=0;
                        flag=0;
                }
                char surfname[4];
                strcpy(surfname,"s0x");
                if(frame<3)surfname[2]='1'+frame;
                        else surfname[2]='1';
                jdd->DrawPicture(backbuffer,surfname,x,312,NULL);
}

void bird_rnd()
{
        jds->Play("woo");
        for(int i=0;i<10;i++){
                birdX[i] = 580;
                birdY[i] = rand()%260+20;
                birdS[i] = rand()%10+5;
                doa[i] = 1;
                jdd->DrawPicture(backbuffer,"bird",birdX[i],birdY[i],NULL);
        }
}

그리고 애니메이션 함수에서 문자열처리가 좀 복잡했는데,
원래 제가 만든 문자열 조합 함수쓰면 한줄에 끝.