I’ve called this page ‘coding’ and not ‘programming’; opting for alliteration over correctness (before anybody is triggered into a comment). I really enjoy casually tackling programming and maths challenges so highly recommend the two websites below if you also share these interests, to develop your skills in languages you prefer.
Although there is a relaxed informal approach of the websites and the challenges are aimed at any level of proficiency (simply choose a challenge appropriate to your competence), they can become very demanding indeed but they’re always captivating. I like challenges that present you problems and rely on you creating ‘a’ solution rather than finding ‘the’ solution.
Project Euler
projecteuler.net contains maths-focussed computational problems for which you can program solutions.
My progress:
Codewars
codewars.com is an educational community for computer programming. On the platform, software developers train on programming challenges known as kata. These discrete programming exercises train a range of skills in a variety of programming languages, and are completed within an online integrated development environment.
My progress:
A video of my attempts at some of the basic challenges on codewars:
Code Abbey
Another coding challenge/practise site exists at codeabbey.com but I have yet to participate.