SDL_CreateRenderer returning nullptr - c++

Question

I'm just starting to learn SDL, and I'm following one of the tutorials I've found, I wrote a simpl code to render a bmp pic to the screen but its not working, the the problem is that the SDL_CreateRenderer is not created (the pointer keeps pointing to nullptr)
dint main (int argc, char* atgs[]) {
int a = 0;
if (SDL_Init(SDL_INIT_EVERYTHING) == -1) {
std::cout << SDL_GetError() << std::endl;
return 1;
}
a = 1;
SDL_Window *win = nullptr;
win = SDL_CreateWindow("Hello World!", 100, 100, 640, 480, SDL_WINDOW_SHOWN);
if (win = nullptr) {
std::cout << SDL_GetError() << std::endl;
return 1;
}
SDL_Renderer *ren = nullptr;
ren = SDL_CreateRenderer(win, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
if (ren == nullptr) {
std::cout << SDL_GetError() << std::endl;
return 1;
}
SDL_Surface *bmp = nullptr;
std::cout << "hello";
bmp = SDL_LoadBMP("c:/hello.bmp");
if (bmp == nullptr) {
std::cout << SDL_GetError() << std::endl;
return 1;
}
SDL_Texture *tex = nullptr;
tex = SDL_CreateTextureFromSurface(ren, bmp);
SDL_FreeSurface(bmp);
SDL_RenderClear(ren);
SDL_RenderCopy(ren, tex, NULL, NULL);
SDL_RenderPresent(ren);
SDL_Delay(2000);
SDL_DestroyTexture(tex);
SDL_DestroyRenderer(ren);
SDL_DestroyWindow(win);
SDL_Quit();
return 0;
}
ren keeps being null, any idea, why?
I though it was because of the computer but I didn't found any problems online, I'm using win 8.1, intel hd4000 graphic card and visual studio 2012.
thx :)

Answer 1

When you create the SDL_Window you perform a check to see if it is null. This is a good thing to do but in your if statement, instead of using an equals comparison operator == you used an assignment operator =
win = SDL_CreateWindow("Hello World!", 100, 100, 640, 480, SDL_WINDOW_SHOWN);
if (win = nullptr) { // This should be if (win == nullptr) {
std::cout << SDL_GetError() << std::endl;
return 1;
}
This allocates null to the win variable and causes SDL_CreateRenderer to return null since that requires a valid SDL_Window