我刚接触linux下编程，所以不懂，麻烦各位帮我看看是什么问题
MQW+NCv#FBLinux伊甸园论坛程序代码
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)P1c9mrS'~]@$cLinux伊甸园论坛#include <stdio.h> za!VX2N
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#include <stdlib.h>
0?gbm&h5c#include <SDL.h>&Hhq!iD@7z
#include <SDL_image.h>
M:b8lVs&H#define DIR_UP 0
B0PP/o7S8CSy%T|Iwww.linuxeden.com#define DIR_LEFT 1www.linuxeden.com,N9["L)_.A4i?
#define DIR_DOWN 2
n#s+p3YzV,jwww.linuxeden.com#define DIR_RIGHT 3(l-z/mLp|g
SDL_Surface *screen;Z?        |yyI |{1u
typedef struct Sprite_t {
0Kp&xmxuX8kint width;
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v&n.aetint height;

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R*Yt~Vint x;
+B*a5G-Zz6IK"|4ITint y;
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int ox;
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{ Zk!vuw5| _m|www.linuxeden.comint oy;
Of0R D:B7G0fint dir;
@m6J'SInZTwww.linuxeden.comint subframe;3m9?*z;]L3c|~
int speed;www.linuxeden.com8n J!MMg        ec#C
int timer;-^xm.o#S
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int moving; //use to calculate subframe8l2z
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SDL_Surface *image;
;b,lnyD4`M8LyG8}}Sprite_t;
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Z9p3O.Etypedef enum GameState {
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y6K;h}c{j9sGAME_RUNNING,
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@LslYGAME_OVER,www.linuxeden.com$_?_jv*O
}GameState;
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q3R9}k8Yvoid Init_SDL() )W'W+T:YG9wE
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if ( SDL_Init( SDL_INIT_VIDEO) < 0 ) {Linux伊甸园论坛?l6y        o/O0n;}
fprintf(stderr,"Can't init SDL: %s\n",SDL_GetError());
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Mexit(1);
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screen = SDL_SetVideoMode(640, 480, 16, SDL_SWSURFACE);Linux伊甸园论坛Yy+}D6uK
if ( screen == NULL ) {
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K3efprintf(stderr, "Error: %s\n",SDL_GetError());www.linuxeden.com/HYEbTp|
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exit(1);
}uZ{3B)irSK%Rwww.linuxeden.com}
8h&U,b'S:j)_:i        ]Oatexit(SDL_Quit);
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void DrawSprite(SDL_Surface *surface,Sprite_t *sprite) Linux伊甸园论坛:e
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SDL_Rect src_rect,des_rect;5u9h3Q }T{N
sprite->subframe=sprite->timer/4;
9F E3z a*J,QF7isrc_rect.w=des_rect.w=sprite->width;www.linuxeden.com)T        UF$pW
src_rect.h=des_rect.h=sprite->height;
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x        Di'CFOsrc_rect.x=sprite->subframe*sprite->width;V _Ged
src_rect.y=sprite->dir*sprite->height;9N
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des_rect.x=sprite->x;

`^?p.qFdes_rect.y=sprite->y;Linux伊甸园论坛F#ZQ;cC1JU5V&E
//Draw sprite to new position O
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SDL_BlitSurface(sprite->image,&src_rect,surface,&des_rect);;Q
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}
v#d0p8n!C,P#@void ClearSprite(SDL_Surface *surface,Sprite_t *sprite) Linux伊甸园论坛N2P9wR$|{3]
{Linux伊甸园论坛b"t"Iz"c[
SDL_Rect mask;Linux伊甸园论坛o%p([GP)R#x
mask.w=sprite->width;sHdYN\I
mask.h=sprite->height;
!L6`IFlU|Z!d+amask.x=sprite->ox;
J{2s&[:r%r6g;Zmask.y=sprite->oy;:F9d[g/k9n:]]
//Clear sprite from the old position
}#y W!`EphLinux伊甸园论坛SDL_FillRect(surface,&mask,SDL_MapRGB(surface->format,0,0,0));
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a#z        H!N;C_Linux伊甸园论坛}3^2N%AC|%T_#c
Uint32 TimeLeft()
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C/lPbg,q%oLinux伊甸园论坛static Uint32 next_time=0;www.linuxeden.come        H"Q |$Fr|g*E1D
Uint32 now;_8l px%u
now=SDL_GetTicks();
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x-Pi7Mwww.linuxeden.comif(next_time<=now){
L]`uQ$es;{next_time=now+30;
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return(next_time-now);
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int main()
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fP6Z!DWQ2bwww.linuxeden.com{
Ux$td} Wwsia        PGameState game_state;www.linuxeden.comY/p3y-z"s
Sprite_t tank;www.linuxeden.com{
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SDL_Event event;B `.F
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Init_SDL();

_}G4n8A1Etank.image=IMG_Load("tank.png");www.linuxeden.com9iI
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SDL_SetColorKey(tank.image,SDL_SRCCOLORKEY,SDL_MapRGB(tank.image->format,255,0,255));Linux伊甸园论坛 QHM%s;q;?
tank.image=SDL_DisplayFormat(tank.image);
2^O?:[;hgame_state=GAME_RUNNING;
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uQx-YALinux伊甸园论坛tank.dir=DIR_RIGHT;
#^9k}$O0`~%h(u!{tank.width=32;
3M{[n2Ztank.height=32;
?$yR*m:T.eRLinux伊甸园论坛tank.x=300;J&`Mv,_u)bX['Z
tank.y=200;&L3l6C"Fit
tank.ox=tank.x;www.linuxeden.com3co4eJ.Dn8n9b
tank.oy=tank.y;
yWX^VcwF(ewww.linuxeden.comtank.moving=0;

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`Linux伊甸园论坛tank.speed=3;pL6`5hG4kN~
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tank.timer=0;

B!fO3y~4tPbLinux伊甸园论坛while(game_state==GAME_RUNNING){B(wcz(dSe5i
ClearSprite(screen,&tank);
Oq.F3X6f0@Zm//Get Inputy&s%]_dy5H
SDL_PollEvent(&event);Linux伊甸园论坛I4R+d;t$s        F!{3k'RsY$Bi
switch(event.type){
H?9QZOM$vlzwww.linuxeden.comcase SDL_KEYDOWN: /d_(Vt kC2nM
switch(event.key.keysym.sym){
2f,Mf^#``N:V        mAk+acwww.linuxeden.comcase SDLK_ESCAPE:qw
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game_state=GAME_OVER;Linux伊甸园论坛9W/Y7y:]sm~
break;
Ew|~*R{`a7^case SDLK_UP:'rOf O
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tank.dir=DIR_UP;
c p;hKTapLinux伊甸园论坛tank.y-=tank.speed;Linux伊甸园论坛1?*?"^/FL'y
break;www.linuxeden.comFF&Ld8^ s'~
case SDLK_DOWN:hW\|i.W`
tank.dir=DIR_DOWN;www.linuxeden.com`4QR(S:]!J
tank.y+=tank.speed;Linux伊甸园论坛HtU']
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break;
1`G"] Ic,r qW;H'dcase SDLK_LEFT:

Wa)mM2M%V+Bf+z tJ0~Linux伊甸园论坛tank.dir=DIR_LEFT;#e;V'J([Ii~        L1K
tank.x-=tank.speed;
\+i~4x1^R*Zbreak;
;^G4U"J(e V#bjLYcase SDLK_RIGHT: WMM-jt6|.lH1J
tank.dir=DIR_RIGHT;.GA&l
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tank.x+=tank.speed;
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|'mwww.linuxeden.combreak;
)WN:|sR#sRX!xgwww.linuxeden.comdefault:
a-N)Q'B;ybreak;
J[mqF,vd"Gyawww.linuxeden.com}
T%H` aLQ&db`Gcase SDL_KEYUP:
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|www.linuxeden.comdefault:
5B;{W]Hbreak;
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D"?d{/D#R0@www.linuxeden.comDrawSprite(screen,&tank);
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ITkxLinux伊甸园论坛tank.ox=tank.x;sfp,z
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tank.oy=tank.y;
9O bi        vGSD"\SDL_UpdateRect(screen,0,0,0,0);
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K&[XHSDL_Delay(TimeLeft()); M4Ar|'jm~"r%U
tank.timer++;i
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tank.timer%=8;
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SDL_FreeSurface(tank.image);
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KLinux伊甸园论坛}Linux伊甸园论坛Q?.rX4r5T C J

4Q7e,cd,G'v}l编译的时候提示

m)o+B|0K#] nf5\x/tmp/ccCxlEey.o(.text+0xlf8):in function 'main'; ?;CZ4[l\'h,ba
test.c:undefined reference to 'IMG_Load'3Euou        s
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collect2:ld 返回 12j)|'K9A*}6I0kyS
是不是tank.image=IMG_Load("tank.png");这句有问题？U
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请各位指点以下我该怎么改，谢谢

是个坦克游戏程序吧，IMG_Load（）函数定义了没有？好像是没定义啊