Invalid window and invalid renderer error SDL c++ - c++

Question

Here is my code
#include <iostream>
#include "SDL.h"
namespace engine {
class SDL_UI
{
protected:
SDL_Renderer* renderer;
SDL_Window* window;
SDL_Event event;
bool initialised = true;
bool quit = false;
public:
SDL_UI(const char* name, int x, int y, int w = SDL_WINDOWPOS_CENTERED, int h = SDL_WINDOWPOS_CENTERED, bool fullscreen = false)
{
if (SDL_Init(SDL_INIT_EVERYTHING) != 0)
{
throw std::runtime_error(SDL_GetError());
}
window = SDL_CreateWindow(name, x, y, w, h, fullscreen);
renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
if (renderer == nullptr)
{
std::cout << SDL_GetError() << std::endl;
//throw std::runtime_error("Renderer creation failed");
initialised = false;
}
if (window == nullptr)
{
std::cout << SDL_GetError() << std::endl;
//throw std::runtime_error("Window creation failed");
initialised = false;
}
}
~SDL_UI()
{
SDL_DestroyWindow(window);
SDL_DestroyRenderer(renderer);
}
void handleEvents()
{
while (SDL_PollEvent(&event))
{
if (event.type == SDL_QUIT)
{
quit = true;
}
}
}
void setColor(int r, int g, int b, int a = 255)
{
SDL_SetRenderDrawColor(renderer, r, g, b, a);
}
void clear(int r, int g, int b, int a = 255)
{
SDL_SetRenderDrawColor(renderer, r, g, b, a);
SDL_RenderClear(renderer);
}
void flip()
{
SDL_RenderPresent(renderer);
}
virtual void update()
{
}
virtual void render()
{
}
void start()
{
if (initialised && !quit)
{
handleEvents();
update();
render();
flip();
}
}
};
class Engine : public SDL_UI
{
public:
Engine(const char* name, int width, int height) : SDL_UI(name, width, height){}
public:
void drawLine(int x1, int y1, int x2, int y2)
{
SDL_RenderDrawLine(renderer, x1, y1, x2, y2);
}
};
}
class Game : public engine::Engine
{
private:
//engine::Draw renderer;
public:
Game() : engine::Engine{ "engine", 1200, 600 }{}
void update() override
{
}
void render() override
{
clear(10, 10, 10);
}
};
int main(int argc, char* argv[])
{
Game game;
game.start();
return 0;
}
I don't get any error message and "invalid window" and "invalid renderer" are printed to the console which are the messages from 'SDL_GetError()'. Window and renderer are created in SDL_UI class's constructor. It checks if renderer and window are nullptr aftet they are created and prints the error if they are still nullptr are creation.

Answer 1

According to this: https://wiki.libsdl.org/SDL_CreateWindow
Function Parameters
title
the title of the window, in UTF-8 encoding
x
the x position of the window, SDL_WINDOWPOS_CENTERED, or SDL_WINDOWPOS_UNDEFINED
y
the y position of the window, SDL_WINDOWPOS_CENTERED, or SDL_WINDOWPOS_UNDEFINED
w
the width of the window, in screen coordinates
h
the height of the window, in screen coordinates
flags
0, or one or more SDL_WindowFlags OR'd together; see Remarks for details
while in your code you have:
int x, int y, int w = SDL_WINDOWPOS_CENTERED, int h = SDL_WINDOWPOS_CENTERED
Try
int x = SDL_WINDOWPOS_CENTERED, int y = SDL_WINDOWPOS_CENTERED, int w, int h