> For the complete documentation index, see [llms.txt](https://wenbo-notes.gitbook.io/cs1010-notes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://wenbo-notes.gitbook.io/cs1010-notes/lec-tut-lab-exes/lecture/lec-12-recap.md). # Lec 12 - Recap Slides: {% embed url="" %} Lecture Slides {% endembed %} ## More on Data Structures A very useful website recommended by Eldon: {% embed url="" %} C Plus Plus Reference {% endembed %} ## Recap of CS1010 > Let's begin the most exciting, impressing and moving but probably the last part of CS1010! :smile: :sob: ## **What have you learned?** > A legit soul searching question. What have I learned in this course? I believe everyone more or less must learn something. But now, let's follow Prof Ooi's steps and have a look at what we've gone through together! ### **1. How to write C** #### **Types** * Use the correct type for the correct data ([Lec 02 - Functions and Types](/cs1010-notes/lec-tut-lab-exes/lecture/lec-02-functions-and-types.md#types)) * Beware of precision issue when using `double` and `float` #### Functions * Write functions that are small and do one thing ([Lec 02 - Functions and Types](/cs1010-notes/lec-tut-lab-exes/lecture/lec-02-functions-and-types.md#writing-good-functions)) > This is legit awesome for me! The specific settings in the `clang` compiler legit force me to think "breaking a big problem into smaller ones"! It #### Operations * arithmetic operations: `+`, `-`, `*`, `/`, `%` ([Lec 03 - Basic C Programming](/cs1010-notes/lec-tut-lab-exes/lecture/lec-03-basic-c-programming.md#arithmetic-operations)) * bit operations in C: `^`, `|`, `&`, `~`, `<<`, `>>` #### Branching and Logical Expressions * Use tables and flowcharts to help you understand the logic and simplify your code. ([Lec 04 - Conditionals](/cs1010-notes/lec-tut-lab-exes/lecture/lec-04-conditionals.md)) * Use assertions to reason about your code. ([Lec 04 - Conditionals](/cs1010-notes/lec-tut-lab-exes/lecture/lec-04-conditionals.md#assertion)) * How to use the `assert` macro * Avoid expressions that are always true or always false. ([Lec 04 - Conditionals](/cs1010-notes/lec-tut-lab-exes/lecture/lec-04-conditionals.md#skipping-else)) * We skipped `switch/case` and `goto` statements. #### Loops * Identify the inital condition, what to repeat, when to stop, what/how to update after each repetition. ([Lec 05 - Loops](/cs1010-notes/lec-tut-lab-exes/lecture/lec-05-loops.md)) * Ensure we move towards the terminating conditions. * Use loop invariants to reason about your loops. ([Lec 05 - Loops](/cs1010-notes/lec-tut-lab-exes/lecture/lec-05-loops.md#loop-invariant)) * We skipped `break` and `continue` statements. #### Arrays and Structs * Composite data types that store multiple values together. ([Lec 06 - Call Stacks, Arrays](/cs1010-notes/lec-tut-lab-exes/lecture/lec-06-call-stacks-arrays.md#fixed-length-array)) * Arrays is useful as a lookup table. ([Lec 09 - Searching and Sorting](/cs1010-notes/lec-tut-lab-exes/lecture/lec-09-searching-and-sorting.md#counting-sort)) * String is nothing but an array with terminating null character (`\0`) ([Lec 07 - Pointers, Memory management](/cs1010-notes/lec-tut-lab-exes/lecture/lec-07-pointers-memory-management.md#string)) * Beware of array out-of-bound errors. * We skipped `union` and `enum`. > Usually, array out-of-bound errors won't be detected by the compiler, so it won't generate compilation error/warning. But, it will generate Runtime Error and usually it is the **segmentation fault.** (See more at [/pages/8xsYKpqqwH8t5zVtOGeM#id-8.-compilation-error-vs.-runtime-error](https://wenbo-notes.gitbook.io/cs1010-notes/lec-tut-lab-exes/lecture/pages/8xsYKpqqwH8t5zVtOGeM#id-8.-compilation-error-vs.-runtime-error "mention")) #### Memory * Arrays decays into pointers. * Using pointers for passing by reference. ([Lec 06 - Call Stacks, Arrays](/cs1010-notes/lec-tut-lab-exes/lecture/lec-06-call-stacks-arrays.md#pass-an-array-to-a-function)) * Effective habits of memory management. > For 1-D array, arrays decay to **memory address of a basic data type variable, e.g. `long`** ([Lec 06 - Call Stacks, Arrays](/cs1010-notes/lec-tut-lab-exes/lecture/lec-06-call-stacks-arrays.md#array-name-decay)). For a 2-D array, arrays decay to the **memory address of a pointer variable**. ([Lec 08 - Multi-d Array, Efficiency](/cs1010-notes/lec-tut-lab-exes/lecture/lec-08-multi-d-array-efficiency.md#array-name-decay-multidimensional-array)) #### Pre-processing * `#include` for headers * `#define` constants and macros * `#ifdef` and `#endif` for conditional compilation > These content are covered in [Lab 08 - C Preprocessor](/cs1010-notes/lec-tut-lab-exes/lab/lab-08-c-preprocessor.md) We focused on writing clean code. Not just code that works. That's why in [#functions](#functions "mention"), we've mentioned that we should write functions that are small and do one thing.
### 2. How a C program behaves #### Memory Model * Stack and heap ([Lec 06 - Call Stacks, Arrays](/cs1010-notes/lec-tut-lab-exes/lecture/lec-06-call-stacks-arrays.md#call-stack) and [Lec 07 - Pointers, Memory management](/cs1010-notes/lec-tut-lab-exes/lecture/lec-07-pointers-memory-management.md#heap)) * Pointers and memory addresses ([Lec 07 - Pointers, Memory management](/cs1010-notes/lec-tut-lab-exes/lecture/lec-07-pointers-memory-management.md#pointers)) * Pass by value vs. pass by reference ([Lec 06 - Call Stacks, Arrays](/cs1010-notes/lec-tut-lab-exes/lecture/lec-06-call-stacks-arrays.md#pass-an-array-to-a-function)) #### Interacting with OS * Proper memory management with `malloc` and `free`. ([Lec 08 - Multi-d Array, Efficiency](/cs1010-notes/lec-tut-lab-exes/lecture/lec-08-multi-d-array-efficiency.md#why-we-cannot-use-free-buckets-here)) ### 3. Tools and Practices #### `clang`, `vim`, `bash`
* Address and bound sanitizer * `clang-format` * `clang-tidy` * `git` * `make` ### 4. Problem Solving Techniques #### Decomposition * Break down the problem into "bite-size" sub-problems * Solve them one-by-one * Compose them back to solve the original problem > There are many valuable Exercises that legit legit practice this "Decomposition" idea! #### Recursion * Solve the "simplest" version. * Assume you can solve the "simpler" version. * Compose the solution to the original problem from the solution of the simpler version. > The idea of "wishful thinking", classic! #### Thinking Tools * Flowcharts * Truth Tables * Assertion and invariants * Test cases ## Computational Thinking The mental process associated with computational problem solving ### Four Pillars of Computational Thinking * Decomposition * Pattern Recognition * Abstraction * Algorithms > If you want to grow up in programming, please don't stop "dirty work", that is coding practically and try these four very very important ideas! #### Decomposition > Decomposition makes a problem easier to solve, reason about, and test George Polya said: "If you can't solve a problem, there is an easier problem that you can solve: find it" * Solve the easier problem first, then generalized. * E.g., [PE1 Review](/cs1010-notes/past-year-exam/pe1-review.md#ex5-q6-social): find two-hops friends, then generalized to k hops * E.g., `pattern`: draw the left most cell, then generalized **Recursion** * Assume the easier problem is solved, then generalized * E.g., `binary`: assume we know how to convey a binary number n-1 digits to decimal, then solve for n digits. * E.g., [Lec 10 - More Recursion](/cs1010-notes/lec-tut-lab-exes/lecture/lec-10-more-recursion.md#tower-of-hanoi): assume we know how to move k-1 discs, then solve for k disc. #### Pattern Recognition > Observe trends and patterns, then generalized **Writing loops** * What to initialize? * What changes from one loop to the next? * Loop invariants > This idea I feel is covered more in designed the search algorithm. e.g., should the bounds be inclusive or exclusive? See more from the tips in [Lec 09 - Searching and Sorting](/cs1010-notes/lec-tut-lab-exes/lecture/lec-09-searching-and-sorting.md#binary-search). Besides searching problem, when you are doing Exercise 6, you also need this skill of *Pattern Recognition*! **Make code shorter and easier to change** * `Taxi` from Exercise 1 > Wah, nostalgic, legit nostalgic :sob: #### **Abstraction** * Identifying and abstracting relevant information * Hide details * Adapt to change * Generalize to other domain **Data Abstraction** > Model the problem with only the necessary information * The string abstarction we've used in [Lec 10 - More Recursion](/cs1010-notes/lec-tut-lab-exes/lecture/lec-10-more-recursion.md#n-queens). **Functional Abstraction** > Hide details and focus on higher-level logic #### **Algorithms** Ways to solve problems * Branches and Loops * Recursion * Memoization with arrays * Divide and Conquer * Exploit properties in data [#four-pillars-of-computational-thinking](#four-pillars-of-computational-thinking "mention") * Decomposition * Pattern Recognition * Abstraction * Algorithms Now, it comes to the end of the recap of the content covered in CS1010. It's a bit disappointing because why the time passes so fast :sob:. But, stay strong and be optimistic, there will be more challenging but interesting courses about coding waiting for you (CS2040C, CS3230, etc). Still remember from Lec 1, Prof Ooi told us:
Lemme go back to the Lec01 Slides, here are the words of advice given by Prof Ooi before the lecture starts:
What great word of advice! After these intense and tough "trainings" by CS1010, I believe more or less you will fell growing up in coding! :clap: > "Grade is not everything. Focus on: learning new things, level-up your skills and enriching your experience!" At last, there is "One more thing..." as usual: ## Special Thanks to... From Prof Ooi: * The tutorial instructors: Eric, Gizem, Yunjeong, Malaika * The lab tutors: (all 25 of them) * The SoC IT Support Team: Tan Hsiao Wei, Lai Zit Seng, and lab technicians * All the students For me, I legit want to express my gratitude to: * Prof Ooi and Dr. Eldon for lectures * Dr. Eric for tutorials * My senior Zhang Puyu for the lab * All my classmates during lab and tutorials > "The course may end, but the journey of learning will never end!"