So I want to start to learn how to code Apps for iPhone. I have basic knowledge of HTML, CSS, C++ and C#. I have not decided yet which program to use: Xcode or Visual Studio Code (I already used second one for other projects). Now...I had this idea of an app with functions like Google Lens - image recognition. I thought maybe I need some kind of database with example pictures? But how do I code that? And how do I program the app to access the camera? Thanks for help.
How to code image recognition
You ask many questions here.
Xcode or Visual Studio Code
I do recommend Xcode. Anyway, you will need it to publish on the AppStore. As for language, if you are fluent in C++, you may select Objective C instead of Swift.
I thought maybe I need some kind of database with example pictures?
Image recognition is now better done with Machine Learning. Here is a tutorial: https : / / w w w .raywenderlich .com/7960296-core-ml-and-vision-tutorial-on-device-training-on-ios
how do I program the app to access the camera?
There are many tutorial about it.
First read Apple's doc:
https://developer.apple.com/documentation/avfoundation/cameras_and_media_capture/avcam_building_a_camera_app