初始化函数SDL_Init()为什么将他放置在主函数之外会出现编译错误，只能放置在main函数里面才不会编译错误？？？？？再问一下我这程序为什么加上初始化函数window只能显示一小会，把初始化函数去掉window却可以一直显示？？？？这是怎么回事
#include <iostream>
#include<SDL2/SDL.h>
#include<SDL2/SDL_mixer.h>
#include<time.h>
#define windowWidth 400
#define windowHeight 600
using namespace std;
SDL_Window* window=SDL_CreateWindow("RLS_Block",SDL_WINDOWPOS_UNDEFINED,SDL_WINDOWPOS_UNDEFINED,windowWidth,windowHeight,SDL_WINDOW_SHOWN);
SDL_Renderer* Rend=SDL_CreateRenderer(window,-1,SDL_RENDERER_ACCELERATED);
SDL_Surface* backImage=SDL_LoadBMP("Image/BackImage.bmp");
SDL_Texture* back_Image_Tex=SDL_CreateTextureFromSurface(Rend,backImage);
SDL_Surface* blockImage=SDL_LoadBMP("Image/block.bmp");
SDL_Texture* block_Image_Tex=SDL_CreateTextureFromSurface(Rend,blockImage);
SDL_Event event;
bool quit=false;
int main(int argc,char* argv[])
{
SDL_Init(SDL_INIT_EVERYTHING);
while(quit==false)
{
while(SDL_PollEvent(&event))
{
if(event.type==SDL_QUIT)
{
quit=true;
}
}
SDL_RenderPresent(Rend);
SDL_Delay(10);
SDL_RenderClear(Rend);
}
SDL_DestroyWindow(window);
SDL_Quit();
return 0;
}