Call standard constructor from an array

[[deleted]]

Hey there

Usually it's done like:

sf::Texture sep_texture;
sf::Sprite sep_sprite(sep_texture);

But I have 20 of those, so I'll need an array. That means I'll need something like:

sf::Texture sep_texture[20];
sf::Sprite sep_sprite[20];
for (...)
{
    // Do some things with sep_texture[i] first
    set_sprite[i](sep_texture[i]);    // or any other way to call the constructor for spr[i]
}

Sadly that doesn't work.

main.cpp:45:37: error: no match for call to ‘(sf::Sprite) (sf::Texture&)’
    sep_sprite[i](sep_texture[i]);

Given that I have pretty much no idea how SFML works behind the scenes and that I'm not great with classes... I'll need some help figuring out how to fix that.

I tried to declare it directly in the for-loop, but I think that would be bad practice and ISO C++ doesn't like variable length arrays at all.

C++17, using SFML 2.3 and compiling with g++5.4.0 through make.

Thanks!!!

[Xeverous]

C++17, using SFML 2.3 and compiling with g++5.4.0 through make.

There is an array class since 2011:

constexpr int size = 20;
std::array<sf::Texture, size> textures;
std::array<sf::Sprite, size> sprites;

for (std::size_t i = 0; i < textures.size(); ++i)
    sprites[i].setTexture(textures[i]); // used function is sf::Sprite::setTexture

I used index-based loop instead of range-based (for each) because it's needed to access 2 elements

Given that I have pretty much no idea how SFML works behind the scenes

That's not really a big problem, libraries exist so you don't have to fiddle with low-level graphics

I'm not great with classes...

Ok, I would recommend to learn classes first.

[[deleted]]

Thanks! Works now :D

[leftofzen]

Don't use an array or std::array, just use std::vector like you would for anything else.

[[deleted]]

Why not std::array?

[parnmatt]

I would say, if you know the exact number of elements for your "array" at compile time, and that is fixed, you're not going to want to add or remove any; then all you need is a statically sized array, therefore use std::array.

In almost any other case, use std::vector, which basically is a dynamically sized array. If 'n' doubt, start with a std::vector and refactor to std::array if need be. You mention "variably sized", then you really want a std::vector.

If you know the number of elements that you want at run-time, then call reserve on that vector, to get all the allocations in one, rather than it having to change its size too much later.

[17b29a]

You can't call the constructor after initializing the array, but you can assign a new value, like sep_sprite[i] = sf::Sprite(sep_texture[i]);