Chapter 27 // Exercise 16 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2022 and ISO C11 Standard.

Chapter 27 // Exercise 16

Use macros to obscure (simplify the notation for) the implementation in the previous exercise.

Github: https://github.com/l-paz91/principles-practice/blob/master/Chapter%2027/Exercises/Exercise%2016.c

Of course the final exercise had to be creating some disgusting macros. And with that

I can't believe that was the final exercise. It's been 7 years. I bought this book back in January 2016 with no knowledge of programming (apart from some brief HTML back in '98) and now I've been programming in C++ for 7 years, 4 and half of them professionally; I get paid to make video games, it's crazy.

I'm going to spend a bit of time collecting my thoughts and then come back with a full review of the book. I think my title is going to be "Why you should learn C++ as your first language". I honestly don't think I would've wanted to learn C++ any other way now.

I've been feeling a bit nostalgic lately and going back over books I bought way back in 2016 and 2017 as well as reading my green text on the early exercises of P&P posted on here. I read a chapter 4 post and the memories of that night came flooding back to me. It took me 6 hours to write a function comparing the size of two ints. It was 3am and I was so frustrated I started crying. I developed a fear of bools. Its absolutely hilarious to me now as I sit here reading a random book, silently ripping apart the authors code because they stored an pointer to an enum.

My mantra at work is "git gud". I can relax a bit when I've "gitten gud", then I can "git gudder". I honestly believed I hadn't really changed at all but lately I've started to realise that I can "just do stuff now". 6 years ago I bought Programming Game AI by Example by Mat Buckland. I tried to read it and follow along with the code but it went completely over my head as I had no experience with inheritance and I was convinced OOP was evil (because I didn't want to understand it). Recently, I picked the book back up and not only implemented the code from snippets with no problem but changed it as I was going along, grumbling about the authors use of singletons and lack of interfaces.

2 years ago I read the online book Ray Tracing in one Weekend and attempted to multi-thread it. It was a disaster and no matter how many times I read MSDN or StackOverflow I just couldn't get my attempts to work. Earlier this year I had another go and got a hacky version working in an afternoon. It's not perfect but it worked and I just "knew" how to do it.

3 months after starting as an intern at Rare, I asked a senior in a catch-up "when do you stop feeling like shit?" and his response was "you don't, but over time it won't be as bad". I pressed him for an actual time for "over time" and he just laughed and said "3 years". It's been 4 years since I asked him that.

It took me a very long time to stop feeling like a waitress/receptionist and start thinking of myself as a programmer. 

Thank you Bjarne for giving me the tools to change my life. 

Chapter 27 // Exercise 15 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2022 and ISO C11 Standard.

Chapter 27 // Exercise 15

Simulate single inheritance in C. let each "base class" contain a pointer to an array of pointers to functions (to simulate virtual functions as freestanding functions taking a pointer to a "base class" object as their first argument); see section 27.2.3. Implement "derivation" by making the "base class" the type of the first member of the derived class. For each class, initialise the array of "virtual functions" appropriately. To test the ideas, implement a version of "the old shape example" with the base and derived draw() just printing out the name of their class. Use only language features and library facilities available in standard C.

Github: https://github.com/l-paz91/principles-practice/blob/master/Chapter%2027/Exercises/Exercise%2015.c

Jesus christ, I had to get ChatGPT in for this one because I had no idea how start. What a load of faffing about. I used to think inheritance in C++ was confusing, well get a load of inheritance in C! It all kind of seems a bit pointless in C. 

I didn't go too far into this exercise, literally just creating the draw() functions for a shape and a circle. Shape can also be created, it's not abstract.

Chapter 27 // Exercise 14 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2022 and ISO C11 Standard.

Chapter 27 // Exercise 14

Write a function that takes an array of ints as its input and finds the smallest and the largest elements. It should also compute the median and mean. Use a struct holding the results as the return value.

Github: https://github.com/l-paz91/principles-practice/blob/master/Chapter%2027/Exercises/Exercise%2014.c

Ah finally, a nicer "easy" one. This reminded me a lot of the exercises we did way back in chapter 4. God, that feels like a lifetime ago.

Chapter 27 // Exercise 13 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2022 and ISO C11 Standard.

Chapter 27 // Exercise 13

Write a program that does the equivalent of strings; cin >> s; in C; that is, define an input operation that reads an arbitrarily long sequence of whitespace-terminated characters into a zero-terminated array of chars.

Github: https://github.com/l-paz91/principles-practice/blob/master/Chapter%2027/Exercises/Exercise%2013.c

I was a bit confused on this one as cin stop reading in characters when it encounters whitespace; have to use getline() to include the whitespace. So with the statement "define an input operation that reads an arbitrarily long sequence of whitespace-terminated characters" I decided instead he meant more of a getline() so we include whitespace characters. So if you were to type "this is a sentence", it captures the entire sentence and prints "this is a sentence". Maybe that's not what he meant though.

Chapter 27 // Exercise 12 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2022 and ISO C11 Standard.

Chapter 27 // Exercise 12

Implement a (C-Style string, int) lookup table with operations such as find(struct table*, const char*), insert(struct table*, const char*, int) and remove(struct table*, const char*). The representation of the table could be and array of a struct pair or pair of arrays (const char*[] and int*); you choose. Also choose return types for your functions. Document your design decisions.

Github: https://github.com/l-paz91/principles-practice/blob/master/Chapter%2027/Exercises/Exercise%2012.c

I originally did a really simple hash function however ended up with collision in the table quickly. I did some searching around and came across the terms "linear probing" where we keep going through slots to find a new one, wrapping round to beginning if needed.

The implementation isn't perfect but it'll do. For my design decisions:

Representation: I chose an array of struct pairs because it keeps the key-value pairs together, which makes it more intuitive.

Return Types: For find(), I return the int value associated with the key. If the key isn't found, I' return a special value, like -1.

For insert(), I return 0 if the insertion was successful and -1 if not (for example, if the table is full).
For remove(), I return 0 if the key was successfully removed and -1 if the key was not found.

Handling Collisions: For simplicity, I handled simple collisions only. This means the table has a fixed size, and if it's full, you can't insert more items.

Capacity: The table has a fixed size, which for this example, is set to 100. it will wrap round to find free slots but after that it won't insert any more.

Chapter 27 // Exercise 10, 11 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2022.

Chapter 27 // Exercise 10

Make a list of C language features adopted from C++ or C with Classes (section 27.1).

Github: N/A

1. Inline Functions: Initially a C++ thing, it lets you suggest to the compiler that a function should be inlined for performance.
2. Single-line Comments: I believe // was first used in B, then brought back in C++ because /**/ is tedious.
3. Variable Declaration Anywhere: Instead of only at the beginning of blocks, you can now declare variables anywhere in C, much like in C++.
4. Mixed Declarations and Code: Kinda related to the previous one. You can intermix variable declarations with executable code.
5. Boolean Type (_Bool or bool with stdbool.h): I was shocked the first time I tried to use a bool in C and found out it had to be added to the language in C89.
6. Compound Literals: Lets you create temporary structures or arrays in the middle of an expression, similar to how you'd do in C++.
7. Designated Initializers: A more expressive way to initialize struct or array members.
8. Static Assertions (_Static_assert): Helps catch errors at compile-time based on constant expressions.

Chapter 27 // Exercise 11

Make a list of C language features not adopted by C++.

Github: N/A

Had to look these ones up. It was actually very interesting.

1. Complex Number Support (_Complex and _Imaginary): C has built-in support for complex numbers, while C++ relies on the std::complex template class.
2. Different Treatment of inline Functions: In C, an inline function's definition can be present in multiple translation units. In C++, inline functions have external linkage by default, but in C they have internal linkage.
3. Allowing Implicit Function Declarations: Older versions of C allowed functions to be called without a previous declaration (not recommended, though!). C++ never allowed this.
4. Named Address Spaces: Some C compilers for specific platforms (like embedded systems) support this feature, but it's not a part of C++.
5. Non-constant Aggregate Initializers: In C, global and static aggregates can be initialized with non-constant values. C++ doesn't allow this.

Chapter 27 // Exercise 9 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2022.

Chapter 27 // Exercise 9

Using only C facilities, including the C standard library, read a sequence of words from stdin and write them to stdout in lexicographical order. Hint: The C sort function is called qsort(); look it up somewhere. Alternatively, insert the words into an ordered list as you read them. There is no C standard library list.

Github: https://github.com/l-paz91/principles-practice/blob/master/Chapter%2027/Exercises/Exercise%209.c

I could not get EOF to work in the slightest with scanf and ctrl+z. I decided to go with the qsort approach because no thank you to the list, so you have to enter the max amount of words to get it to quite the loop. Sometimes it would register the EOF, sometimes it wouldn't, sometimes I had to spam it on the keyboard and it would eventually register it.

Chapter 27 // Exercise 8 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2022.

Chapter 27 // Exercise 8

What is the lexicographical order on your machine? Write out every character on your keyboard together with its integer value; then, write the characters out in the order determined by their integer value.

Github: https://github.com/l-paz91/principles-practice/blob/master/Chapter%2027/Exercises/Exercise%208.c

Ah finally, a nice "easy" one. Although I kind of cheated. I basically just looped through the ascii table from 0 to 255 and printed everything. I think maybe he wanted us to actually write a string and fill it with the actual characters on our keyboard but I have no idea how to get special characters out of my keyboard so I just left it to the for loop.

Chapter 27 // Exercise 6, 7 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2022.

Chapter 27 // Exercise 6

Change the representation of Link and List from section 27.9 without changing the user interface provided by the functions. Allocate Links in an array of links and have the members first, last, pre, and suc be ints (indices into the array).

Github: https://github.com/l-paz91/principles-practice/blob/master/Chapter%2027/Exercises/Exercise%206.c

I honestly had no idea what he meant when I read this so I asked ChatGPT to explain it to me like I'm 5. It was very helpful and I realised that what he wanted us to do was kind of create a vector where you can traverse the list via an index and then access the data at that index.

I had a stab at it for a couple of hours but honestly, my head just wasn't in it. I cannot stand anything to do with linked lists, never mind linked lists in C. So I left it half finished. The code I linked above kind of works but it also kinda doesn't.

Chapter 27 // Exercise 7

What are the advantages and disadvantages of intrusive containers compared to C++ standard (non-intrusive) containers? Make a list of pros and cons.

Github: N/A

I won't write an entire essay but from what I've seen intrusive containers would've been very normal back when C ruled the land. They're extremely lightweight versions of C++ templated containers, only you don't get the flexibility/generic-ness of the templated container but you get better performance. 

I suppose they would be useful in embedded systems where you know exactly what you're working with and have specific memory constraints. 

Chapter 27 // Exercise 4, 5 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2022.

Chapter 27 // Exercise 4

If you didn't already, write a C++ version of the intrusive List example in section 27.9 and test it using every function.

Github: https://github.com/l-paz91/principles-practice/tree/master/Chapter%2027/Exercises/Exercise%204

This took me a good hour. I still hate linked lists. For this one I decided to make the list templated instead of Name storing a linked list. All the functions are now part of the list and I considered having it use a std::unique_ptr but in the end decided to just go with new and delete as the whole point of an intrusive list is to be as efficient as possible.

Chapter 27 // Exercise 5

Compare results of exercises 3 and 4.

Github: N/A

I think it's obvious that I much prefer exercise 4. I don't like having all the functions on their own, the classes aren't managing their own memory and the syntax to create new ones of different types is just hideous. 

Chapter 27 // Exercise 2, 3 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2019 and ISO C11 Standard.

Chapter 27 // Exercise 2

Complete the intrusive List example in section 27.9 and test it using every function.

Github: https://github.com/l-paz91/principles-practice/blob/master/Chapter%2027/Exercises/Exercise%202.c

This was quite a painful exercise. Mainly because I hate linked lists and they confuse me with their mPrev->mNext->mPrev malarky but this time I had to do it in C! C also just has so many parenthesis.

Chapter 27 // Exercise 3

"Pretty up" the intrusive List example in section 27.9 as best you can to make it convenient to use. Do catch/handle as many errors as you can. it is fair game to change the details of the struct definitions, to use macros, whatever.

So I turned the code into my usual style and found a bug? I'm not sure but I couldn't get it to run using the code in the book. In the main() function it needs to be struct Link* curr. I think he did that on purpose though as the for loop doesn't work otherwise because a List doesn't have suc as a member variable.

Apart from that, I didn't really bother with the other things.

Chapter 27 // Exercise 1 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2019 and ISO C11 Standard.

Chapter 27 // Exercise 1

Implement versions of strlen(), strcmp(), strcpy().

Github: https://github.com/l-paz91/principles-practice/blob/master/Chapter%2027/Exercises/Exercise%201.c

I feel like I'm being punished. Please let me go back to C++, I swear I'll be good.