what is the best language to cod ! and support all platform

C

Scratch

World at War, definitely my favourite cod

*sigh*....

Java, c++, Python, JS. Plenty of options around these parts. I like Java for cross platform guis although you can use JS as well if you are already well versed in web development.

C++ is one of the best options as well for practically anything you would want to create. There is plenty of room to choose from, pick a lang that you like the most because even TCL can be used for cross platform development.

I found java better than python in platform support, but both are great!

Mips assembly is the best.

I'm with @AleCx04 on this. As long as we're not talking about web development: C++ and Java.

Reasons:
C++ opens up the world of C languages (C, C++, C#). It's a good language on its own, and you can apply that knowledge on an Arduino.

Java is a powerful tool with lots of references. You can then move to Kotlin (or not) to make Android apps.

There's a whole lot more to these languages, but that's what I got at the moment.

Python is beautiful language, but I feel that you will appreciate it more when you see what it does different (compared to C++ and Java).

At the end of the day you can use any language you're comfortable with. Chances are that there's a way to make a program with the language on every platform.