I'm completing these puzzles using a different programming language every day. I chose the languages from ones I've used either professionally or on side projects over the past 40 years that I've been programming. I'm doing them in roughly the order in which I learned them.
The years after each language are approximately when I was actively using it.
Day 1: BASIC (1978-1985)
Day 2: 6502 Assembly (1982-1986)
Day 3: Pascal (1984-1989)
Day 4: C (1986-2005+)
Day 5: Lisp (1988-1990)
Day 6: Smalltalk (1988)
Day 7: Rexx (1988-1993)
Day 8: BASH (1990-present)
Day 9: Ada (1990-2007)
Day 10: C++ (1991-2005, 2020-present)
Day 11: Tcl (~1995)
Day 12: Java (1998-2007, 2015-present)
Day 13: Objective-C (2007-present)
Day 14: C# (2007-present)
Day 15: JavaScript (2010-present)
Day 16: Scala (2014) -- part 1 only
Day 17: Groovy (2014-present)
Day 18: Ruby (2015-present)
Day 19: Swift (2014-present)
Day 20: TypeScript (2019-present)
Day 21: Kotlin (2020-present)
Day 22: Python (2020-present) -- part 1 only
Day 23: Dart (2021-present)
Day 24: Rust (2022-present)
Day 25: SAIL (2014-present)
To run these, you'll need to download your input files.
These should be saved in a file named input.txt in the same directory as the puzzle solution.
Each day's folder has a makefile that attempts to download that day's input for you.
In order for this to work, you have to have a file named .aoc-session in your home directory.
That file should contain the value of the session cookie used by AoC to authenticate you.
See this for a quick explanation of how to get the session cookie for your account.