Programming

I did a lot of research the other day about what I’d need to build a contact form for my website. I bookmarked lots of pages. And today, I come and look at this mountain of videos and sites and pages and woneder what exactly it is, that I am supposed to tackle. Nothing makes sense. I know I ruled out Sendy as an option. Or did I? Do I need Javascript? How much? Can I get snippets to copy paste? Do I need to go learn Javascript? What is spam protection? Do I need spam protection? How do I do it? I’ll have to go look at it all again now.1 ...

Using Abdul Bari’s, Mastering Data Structures & Algorithms using C and C++ to grok the basics. Now that I grok programming, understanding DSA should help me write and think better. And writing rough notes or thoughts to myself here, keeps me accountable and on track.1 Today’s topic? The Basics of Recursion Types of Recursion Tail Recursion Head Recursion Tree Recursion Indirect Recursion Nested Recursion Tail Recursion When a recursive call, is the last statement in a recursive function, that’s tail recursion func(n) { if (n>0) { blah … ; blah … ; blah … ; func(n-1); } } All the operations in the examples above happen at call time. Not when the function returns Tail Recursion vs Loops Tail recursion function can be written as a loop and vice versa Time taken by both, O(n) But the space taken by a loop is O(1) while a tail recursive function is O(n). The loop takes less space. Some compilers also do this under the hood (convert a tail recursive function into a loop) Head Recursion func(n) { if (n>0) { func(n-1); blah … ; blah … ; blah … ; } } In the example above, the recursion happens before anything else takes place. the recursion call is the first statement the rest of the function is processed, in the return process. (i.e. once the recursion call is done executing) Head Recursion vs Loops Head recursion function and a loop that gives a corresponding output are not quiet convertible from one to the other. Some work required. Tree Recursion func(n) { if (n>0) { blah … ; func(n-1); blah … ; func(n-1); blah … ; } } If a function calls itself multiple times, then we have ourselves a tree recursion Time complexity? pretty complex. A simple thing like the one above would be O(2n), while the space complexity is O(n) Indirect Recursion void A (int n) { if (something-something) { blah … ; B(n-1); } } void B (int n) { if (something-something) { blah … ; a(n-1); } } Two (or more) functions calling each other in a circular fashion. A -> B -> C -> A Nested Recursion void fun(int n) { if (blah-something) { blah fun(fun(n-1)) } } A recursive function passes a recursive call to itself as a parameter to the function. P.S. Subscribe to my mailing list! Forward these posts and letters to your friends and get them to subscribe! P.P.S. Feed my insatiable reading habit. ...

Org mode is slowly spreading its tentacles increasingly becoming something, I cannot live without, to manage my day. And I’m getting pretty consistent with it too! Like you see above, I use dates as my headlines, below which I list the various tasks for the day.1 And that’s where I run into my current itch to scratch. ...

Originally published 2021/10/27. Updated to include the .xssessionsrc point I run pretty often into this issue, so this is a checklist for me. Issue being, that I cannot use Compose key sequences to type out the characters I need. Case in point being, the apostrophe ’ and the quote marks “” , ‘’ that I use, all the live long day. Make sure that emacs is running as a service. It runs in your user, so check status with systemctl --user status emacs.service Do the normal computer user thing. Restart the service.systemctl --user restart emacs.service.1 Make sure the system is UTF-8 everywhere. (en_IN.UTF-8 does not work for me. Make sure it’s en_US.UTF-8) One place that Emacs looks is the .xsessionrc file in the home folder. These are the contents of mine. My Emacs refuses to let the compose key sequences work, unless it’s present LC_NUMERIC=en_US.UTF-8 LC_MONETARY=en_US.UTF-8 LC_PAPER=en_US.UTF-8 LC_NAME=en_US.UTF-8 LC_ADDRESS=en_US.UTF-8 LC_TELEPHONE=en_US.UTF-8 LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=en_US.UTF-8 LC_TIME=en_US.UTF-8 PAPERSIZE=a4 LANGUAGE=en_US LANG=en_US.UTF-8 if [ $DISPLAY != ":0" ] then export XAUTHORITY=${HOME}/.Xauthority fi This should do the trick 99% of the time. ...

Did I not just write about this, the other day with Emacs? I did, but Pycharm seems to have the same affliction. Pycharm, just like Emacs, stubbornly refuses to accept my Compose key combinations. Which means … you guessed it, no ‘,”,“ or ’ punctuation and all the other affordances, Compose gives me. Considering that I need both, Pycharm as well as Emacs in my life, it behooved me, that I go solve this too. ...

Shoutouts of Gratitude to the teachers who I learnt programming from over the past couple of years … Kushal Das, for bringing me in, teaching me the ropes and assuring me there was a place for me here Reuven Lerner, who unravelled Python for me and made me realise that languages were small, and the reason I was struggling was not Python, but because I wanted to understand all of computer science in too short a time frame.1 ...