Which program language is the most important for programmers?

Answer 1

HTML - websites
PHP - maintaining servers
Swift - Developing apple apps
Java - Generally, anything goes
C# - Windows applications, games
C - program irl things
Python - Science
C++ - make games
Ruby = scripting and automation

Answer 2

it really depends on what you wonna do. dev web front end HTML and Css, back end PHP, SQL... App dev ou prog choose one of the main langage stick to it. No need to know them all. C++ may ne the most powerfull but not the easiest one.

Answer 3

The one you know well and answer your needs. For Web projects html+js+css+php but for desktop application csharp and java is cool but if you want to write application for ios you should know swift.

so there is no magical one answer; the answer is depends on your needs.