重点
初学SDL2，此处为笔记。有错误还请指出。
13)When our SDL 2 application runs, the operating system needs to be able to find the dll file.
Go find the SDL 2 lib folder you extracted and copy SDL2.dll and put it either your project's working directory (where the vcxproj file is at), or inside of the system directory. C:WINDOWSSYSTEM32 is the 32bit windows system directory and C:WindowsSysWOW64 is the 64bit system directory of 32bit applications. For these tutorials, I'm assuming we're making 32bit applications.
备注：
在运行时需要SDL2.dll，关于SDL2.dll的位置，有两种方案：
方案一： 需要将SDL2.dll文件放到工程目录的vcxproj文件所在。独立运行生成的exe程序，需要将SDL2.dll放到exe所在目录。
方案二：如原文所述将SDL2.dll文件放到C:WINDOWSSYSTEM32 或者C:WindowsSysWOW64 目录中（64位操作系统就放到SysWOW64目录，32位操作系统放到SYSTEM32目录）
SDL虚拟键映射表