hello SDL

#include “sdl.h”
#include <stdlib.h>

SDL_Window* sdlwindow=NULL;
const int SCREEN_WIDTH=640;
const int SCREEN_HEIGHT=480;
SDL_Surface* g_pDisplaySurface = NULL;
SDL_Event g_Event;
SDL_Rect g_Rect;
Uint8 g_Red, g_Green, g_Blue;
Uint32 g_Color;

int main(int argc, char* argv[])
{
    SDL_Init(SDL_INIT_VIDEO);
    atexit(SDL_Quit);
    sdlwindow=SDL_CreateWindow("title",
        SDL_WINDOWPOS_CENTERED,
        SDL_WINDOWPOS_CENTERED,
        SCREEN_WIDTH,
        SCREEN_HEIGHT,
        SDL_WINDOW_SHOWN|SDL_WINDOW_BORDERLESS//无边框
    );

    g_pDisplaySurface = SDL_GetWindowSurface(sdlwindow);
    
    for(;;)
    {
        if(SDL_PollEvent(&g_Event)==0)
        {
            g_Red=rand()%256;
            g_Green=rand()%256;
            g_Blue=rand()%256;
            g_Color=SDL_MapRGB(g_pDisplaySurface-
            >format,g_Red,g_Green,g_Blue);
            g_Rect.x=rand()%SCREEN_WIDTH;
            g_Rect.y=rand()%SCREEN_HEIGHT;
            g_Rect.w=rand()%(SCREEN_WIDTH-g_Rect.x);
            g_Rect.h=rand()%(SCREEN_HEIGHT-g_Rect.y);
            SDL_FillRect(g_pDisplaySurface,&g_Rect,g_Color);
            SDL_UpdateRect(g_pDisplaySurface,0,0,0,0);
        }
        else
        {
            if(g_Event.type==SDL_QUIT) break;
        }
    }
    return(0);
}