Using scanf to get user input from console

In C, you can use scanf to get character input from console. However, if you do it multiple times, you will realize that pressing enter after the first scanf affects the next scanf call. This happens when you have a space after your prompt, e.g. printf("Choice: "); char c; scanf("%c"). Either don't put a space at the end of printf or use a space in scanf like so: scanf(" %c")

When is inheritance useful?

A major disadvantage of inheritance is not being able to follow the program flow by ctrl + clicking function calls due to some functionality being implemented in ancestor classes. Therefore, I prefer composition over inheritance whenever possible. The one case where inheritance shines is reusing workflows. Let's say all your child classes have a run() method that calls f1(), f2() and f2() in order, where f1, f2, f3 functions are implemented in child classes. If we move the run() method to the ancestor class, child classes would just call that run method, saving you from duplicating the f1, f2, f3 calls in each child.

Studying Algorithms and Data Structures Effectively

There are many ways to solve programming problems. The ideal solution is the one running the fastest and consuming the least amount of memory. The field of algorithms and data structures equips you with the tools to find the best solution. A good solution might run  a million times faster than a naive/brute force solution, which might be the difference between a successful and failed project. It has similarities to mathematics because mathematics always tries to find more concise formulae. For example you can find the sum of consecutive integers from 1 to n by summing each number one by one which has a time complexity of O(n). Or you could think a little more about the problem and observe that there are n/2 pairs of the value of n+1, yielding the famous Gauss formula of n/2*(n+1), which has a time complexity of O(1), i.e. the brute force method gets slower and slower as n increases while the formula always runs at constant time! See a similar Codility problem. A good solution is also environmentally friendly since it consumes less energy.

When studying algorithms and data structures, besides course material, I recommend solving the relevant leetcode questions. Start with the easy ones but note that if this is your first attempt at solving "easy" questions, they won't be easy at all, watch this video for a general approach. Don't just focus on the answer, analyze your solution process even after your solution passes all tests so that it really sinks in.

The good news is that once you solve easy questions, medium ones are not that difficult. The website NeetCode organizes problems nicely according to data structure type and difficulty, I personally use the NeetCode 150 group (see my notes). Python is a concise language to solve coding problems, this 26 minute video teaches you enough python for that. After you finish 29 easy questions on NeetCode 150, move to medium questions, and finally solve the hard ones. It will probably take a couple of months to solve all 150 questions. Besides strengthening you algorithms and data structures foundation, you also will have practiced for coding interviews.

If you want to practice more in a specific area, you can use chatGPT to generate additional questions/problems, e.g. "generate a medium level coding question related to trie data structure"

Visualizing algorithms: Visualgo

05.10.2025: For junior roles, consider this smaller set of 49 questions curated by Aman Manazir, designed to be completed in 8 weeks:

ARRAYS & HASHING

01	Easy	Contains Duplicate
02	Easy	Valid Anagram
03	Easy	Two Sum
04	Medium	Group Anagrams
05	Medium	Top K Frequent Elements
06	Medium	Valid Sudoku
07	Medium	Product of Array Except Self
08	Medium	Longest Consecutive Sequence

TWO POINTERS

09	Easy	Valid Palindrome
10	Medium	Two Sum II Input Array Is Sorted
11	Medium	3Sum
12	Medium	Container With Most Water

SLIDING WINDOW

13	Easy	Best Time to Buy And Sell Stock
14	Medium	Longest Substring Without Repeating Characters
15	Medium	Longest Repeating Character Replacement

STACK

16	Easy	Valid Parentheses
17	Medium	Min Stack
18	Medium	Daily Temperatures

BINARY SEARCH

19	Easy	Binary Search
20	Medium	Find Minimum In Rotated Sorted Array
21	Medium	Search In Rotated Sorted Array

LINKED LIST

22	Easy	Reverse Linked List
23	Easy	Merge Two Sorted Lists
24	Medium	Reorder List
25	Medium	Remove Nth Node From End of List
26	Easy	Linked List Cycle
27	Medium	LRU Cache

TREES

28	Easy	Invert Binary Tree
29	Easy	Maximum Depth of Binary Tree
30	Easy	Diameter of Binary Tree
31	Easy	Balanced Binary Tree
32	Easy	Same Tree
33	Easy	Subtree of Another Tree
34	Medium	Lowest Common Ancestor of a Binary Search Tree
35	Medium	Binary Tree Level Order Traversal
36	Medium	Binary Tree Right Side View
37	Medium	Count Good Nodes In Binary Tree
38	Medium	Validate Binary Search Tree
39	Medium	Kth Smallest Element In a Bst

HEAP / PRIORITY QUEUE

40	Easy	Kth Largest Element In a Stream
41	Easy	Last Stone Weight
42	Medium	Kth Largest Element In An Array

GRAPHS

43	Medium	Number of Islands
44	Medium	Max Area of Island
45	Medium	Clone Graph
46	Medium	Pacific Atlantic Water Flow
47	Medium	Surrounded Regions
48	Medium	Course Schedule
49	Medium	Course Schedule II

29.10.2025: leetcode-75

Leetcode notes

You can find solutions of Leetcode problems online. Sometimes my own solutions are more intuitive to me. Here I present my solutions that I find interesting in Python3 and my notes.

Behavioral interview preparation as a student

From Google to Toptal, behavioral questions are an integral part of the interview process. Questions like "what did you do when you realized that the deadline could not be met", "tell me about a case where your teammate was underperforming and your response" try to assess your communication and conflict resolution skills. As a student, you should treat such crisis as opportunites. A bad way to handle teammates that do not shoulder their share is to quarrel with them and take their share too without trying to negotiate a settlement. You should at least get their point of view in a coolheaded manner. Even if you cannot win them over for the cause, you will improve your communication skills and you will have stories to tell in interviews. Watch this video for tips.

Podcast with a sofware engineer working in Munich

I recently did a podcast (in Turkish) with my cousin who works as the software engineering department head of a company in Munich. In it, we also answered the following questions which were previously asked by my mentee, Nansy:

Question: Did he have to learn on his own or was his university knowledge sufficient?
Answer: You have to learn on your own too.

Question: How important is GPA really?
Answer: Not much if you don't plan to do graduate studies. If your GPA is not great, you have to be able to give reasons for it. Good reasons: Worked on my projects/hobbies, worked part time, traveled around the world. Bad reasons: Watched movies, played games.

Question: How can someone decide which area/language/framework to learn and focus on when there are so many?
Answer: Picking an industry/sector will narrow down the selection. Make sure that your computer engineering fundamentals like algorithms and data structures are sound.

Summer project ideas

Software project ideas for summer 2022:

1. Web Application:

1.1. [PHP] Create a WordPress plugin to rent expensive dresses. It should have a calendar for rent start-end dates. Payment should use iyzico sandbox. It should support vendor/product review.

1.2. Create a multi-vendor Shopify app, similar to and better than Multi Vendor Marketplace. Look at its negative reviews for inspiration, e.g. "looks very trashy and confusing", "error-free bulk data upload"

1.3. Leetcode clone for embedded software development: Exercises and unit tests, board simulators (timer, interrupt, peripheral sim (RAM, SSD, NIC) for driver writing exercises). Vision: Become the TopTal of embedded software development.

1.4. Clone Twitter (simplified LeetCode problem)

1.5. Build a Google Docs clone.

1.6. Build a Codility clone. Step 1: Online code compiler

1.7. Write a Chrome extension to create gif

2. Mobile app: 

2.1. Develop an Android application that gets video from a PC using the mobile hotspot on the phone:

2.2. Payment sharing/bill splitting between a group of friends

3. Automotive:

2.1. Write a simple 2D self driving car demo.

2.2. Collect acceleration data from an RC car, send it to the cloud, on the cloud backend identify road quality from acceleration data and show it on a web page.

2.3. Make openpilot work on CARLA.

4. Website development: Find an existing website that has performance issues, do performance profiling and write a faster  version of it.

5. Finance, cryptocurrency, cybersecurity: 

5.1. Write a Lightning Network clone

5.2. Develop an air gapped Bitcoin wallet.

5.3. Write a uTorrent clone (peer to peer distributed file sharing)

6. Gaming: 

6.1 Write a game that involves puzzle piece placement and path finding and runs in the browser.

6.2. Write a peer-to-peer real time multiplayer game that uses the lockstep protocol (see consensus).

6.3 Clone Just Dance Now. Convert it to use webcam to detect and rate your movement accuracy.

7. Music: Write an app that normalizes sound levels of tracks in a playlist so that the user does not have to fiddle with the volume setting.

8. Aerospace: 

8.1. Write a web app that lets the user change kinematic parameters of a simple aircraft and observe the effects on a 2D trajectory.

8.2. Write a web app that does a simplified 2D version of the moon landing, including orbital calculations.

9. Miscellaneous:

9.1. Improve GeoTools: 

• Create a fork and push your updates to this fork.
• Draw a polygon (e.g. hexagon) on map. Zoom - unzoom with mouse wheel. Drawing should be updated while zooming, it should not wait until mouse wheel stops.
• Pan with the right mouse click and drag. Drawing should be updated while panning, it should not wait until mouse button is released.
• Show country borders.
• On startup, map should center on Turkey and Turkey borders should fill the view.
• Document your progress/challenges, preferably create a public blog and write a developer diary there.

To generate more software project ideas, you can use chatGPT, ProductHunt and KickStarter