쉐도잉 연습: you will never ask about pointers again after watching this video - 영상으로 영어 말하기 배우기
레슨 만드는 중...
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One of the hardest things for new programmers to learn is pointers.
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Whether it's pointers by themselves, pointers that point to arrays, or pointers that point to pointers, Something about this concept just drives people crazy.
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And if you're a new programmer, well, you're not alone.
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I was one of those people when I learned C back in the day, and like you, I was eager to understand.
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In this video, I'll show you what a pointer is so you can fully understand how they work, the syntax of pointers so you can easily read them,
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and finally, why everyone cares so much about pointers and what they're used for.
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Before we start, if you're new here, hit that subscribe button and while you're at it leave a like.
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I put out videos demystifying topics like this and much more on a weekly basis.
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What is a pointer?
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The question that's been asked since the beginning of time.
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well, maybe not that long, but computer science students have been asking this question for a while.
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Pointers are not that complicated, and let me show you why.
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To understand what a pointer is, we need to first understand how memory works.
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So here I've laid out an example of memory.
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Memory in our example has two features: an address, and a value.
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The address is the location of the memory, meaning where that memory lives.
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And the value of that memory is the data stored at that location, meaning what memory lives there.
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So for example, if I put a four here, What does that mean?
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All that means is that the value 4 lives at location hex 1000.
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Easy.
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And the notation in C, for example, may be int x equals four, which gets allocated to that memory on the stack, and now that number lives there.
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So what happens now if at another location I put the number hex 1000 at address hex 1004?
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I've just created a pointer.
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You may be thinking, low level learning, how is this possible?
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That's just a number at a location.
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Well guys, that's the secret.
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A pointer is just a value that happens to be an address.
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Mind blown.
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By setting the value of one variable equal to the address of another, that variable now points to the other.
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For new programmers, though, most of the time, that isn't as easy as it seems.
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One of the most common issues new programmers have with pointers is the syntax used to create them.
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The combination of stars and ampersands and arrows and more stars creates a lot of confusion, so let's break this down using our previous example.
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In our last example, we made an integer x whose value was 4 at location hex 1000.
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After that, we made a pointer that lived at address hex 1004, whose value was $1000.
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So how do we do that in C?
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We can do that using two lines of code, and I'll break them down part by part.
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The first line is int x equals four.
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This line is pretty straightforward.
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The first part, integer, is the type of the variable, which is 4 bytes wide, and this will matter later in the video.
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The second part is the name.
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Nothing special here, just the variable name x.
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And then after that, we put an equal sign, which when describing C, we can verbalize the equal sign to is C set to.
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Finally, the value 4.
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So the final sentence we've come up with is, Integer whose name is X is set to the value 4.
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Okay.
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Easy part over, next is the hard part.
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To make a pointer to x like we did in our example, I would say the following line of C: int *px is equal to ampersand x.
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Now I know that sounds pretty crazy, a little scary, Let's break it down piece by piece.
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From left to right, we can see the type again, starting with int.
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But next we see the dreaded Asterisk.
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What does that mean?
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When an asterisk is placed next to a type, it modifies the type, meaning that our variable is now a pointer to an integer.
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So our variable here points to a four byte value.
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Next, the variable's name which is Px or pointer to x, You can name it whatever you want, but this is a good habit using "P" to denote that it's a pointer.
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and then after that are equal sign, which again means is set to.
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Ah, and then the next dreaded character, the Ampersand.
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Whenever you see an ampersand just think in your head the address of.
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So this means the address of x.
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Our final sentence here is, Int pointer.
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P X is set to the address of X.
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So, what does this do for us?
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Well now by using the pointer, we have a way of accessing x by reference instead of by value.
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So for example, if we wanted to copy the value of x to a new variable using that pointer, we could do that pretty easily with this new bit of code.
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We'll say that int y equals *px.
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Now what is this code doing?
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Let's break it down.
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Again, y, just like x, is a normal integer, so no pointers yet.
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We say that Y is set to, using that equal sign, uh oh, the asterisk again.
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Remember how last time I said when we see an asterisk, it's used to modify a type if a type is near it?
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Well, here there is no type.
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When it's used alone this way, the asterisk is referred to as a "d" reference.
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The dereference means go to the address pointed to by the pointer and grab that value.
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So, because px points to x, The dereference will go and grab that value and it will set Y equal to x.
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So when reverbalizing C, when you see an asterisk by itself, you can say "the thing pointed to by."
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This would mean that the final verbalization of this line of C is
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integer y is set to the thing pointed to by p x.
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By doing this, we can pass around X by reference instead of value.
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And why that matters, I'll explain in the next part of the video.
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The final concept that could use people the most when learning about pointers is why does anyone use them?
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The syntax is confusing, my programs crash all the time when I use them, why does anyone bother?
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Well, the answer is because we have to.
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To avoid making code that is impossible to read or unscalable, we break down functions based on the action that they perform,
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So here I have a small snippet of C where I have a function that updates the age of a person structure.
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The problem is that the structure I'm editing is not in scope of the editing function.
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To get around this, we pass the struct by reference so that now the pointer to the structure
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is in scope of update struct and can therefore be edited.
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Using pointers like this keeps our code clean and understandable while reducing the amount of space that we use by not copying.
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Another reason that pointers are inevitable when coding in C is the idea of using static versus dynamic memory allocation.
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static allocation is typically a variable that goes onto the stack, a place that is always in scope for the function that is running it.
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However, when you're using dynamic allocations that come from the heap through malloc or sbreak or other kinds of memory allocators,
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you are going to get a pointer to memory that is out of scope.
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If you ever want to be able to use this kind of memory, you need to know how pointers work.
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The primary difference between dynamic and static allocations is
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that static allocations are things
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that are known to have a fixed size at compile time
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whereas dynamic allocations can be changed in size as the program runs.
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Here you see I allocate a string of 100 bytes to be pulled from the heap
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But that 100 bytes could have come from a user input or something else.
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If you're having a hard time with C, don't be discouraged.
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Pointers do take a minute to master, but once you get them, you'll know it and you'll feel like a real low level wizard when you do.
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Guys, I had a fun time making this video.
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If you enjoyed this, do me a favor, hit like, hit subscribe, and I'll see you next week.
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Take care.
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이 레슨의 어휘와 말하기 포인트
이 영상에는 섀도잉할 문장 103개와 단어 1434개가 있습니다. 말하는 구간의 길이는 7:59입니다. 화자는 분당 약 180단어로 빠르게 말하므로 연음과 약하게 발음되는 소리가 많습니다. 영어에서 가장 많이 쓰이는 3,000단어에 속하는 단어가 81%뿐이라 어휘가 어려운 편입니다.
이 영상의 핵심 어휘
영상에 나오는 덜 흔한 단어 15개를 발음, 뜻과 함께 정리했습니다.
- pointer /ˈpɔɪn.təɹ/ (명사) — 교편. One who points.
- programmer /ˈpɹoʊɡɹæmɚ/ (명사) — 프로그래머. One who writes computer programs.
- edit /ˈɛdɪt/ (동사) — 편집하다. To change a text, or a document.
- syntax /ˈsɪn.tæks/ (명사) — 통어론, 구문론. A set of rules that govern how words are combined to form phrases and sentences.
- stack /stæk/ (명사) — 무더기. A large pile of hay, grain, straw, or the like, larger at the bottom than the top, sometimes covered with thatch.
- subscribe /səbˈskɹaɪb/ (동사) — 구독하다. To write (one’s name) at the bottom of a document; to sign (one's name).
- modify /ˈmɑ.dɪˌfaɪ/ (동사) — 수정하다. To change part of.
- topic /ˈtɑpɪk/ (명사) — 화제, 주제. A subject; a theme; a category or general area of interest.
- complicated /ˈkɑm.plɪˌkeɪ.tɪd/ (형용사) — 복잡하다. Difficult or convoluted.
- refer /ɹɪˈfɜː/ (동사) — 언급하다. To direct the attention of (someone toward something).
- string /stɹɪŋ/ (명사) — 끈. A long, thin and flexible structure made from threads twisted together.
- scary /ˈskɛə.ɹi/ (형용사) — 공포의, 무섭다. Causing fear or anxiety
- versus /ˈvɝsəs/ — 대. Against; in opposition to.
- habit /ˈhæb.ɪt/ (명사) — 습관, 버릇. An action performed on a regular basis.
- confusion /kənˈfjuːʒən/ (명사) — 혼란. A lack of clarity or order.
주의할 발음
화자는 you're, I'll, I've 같은 축약형과 약화된 형태를 20번 사용합니다. 들리는 대로 짧게 발음하세요.
- “sh”와 “zh” 소리: allocation /ˌæl.əˈkeɪ.ʃən/, confusion /kənˈfjuːʒən/, notation /noʊˈteɪʃən/
- 긴 단어 — 강세 위치에 주의: allocation /ˌæl.əˈkeɪ.ʃən/, complicated /ˈkɑm.plɪˌkeɪ.tɪd/, inevitable /ɪˈnɛvɪtəbəl/, allocator /ˈæl.ə.keɪ.tə/, demystify /diːˈmɪstɪfaɪ/
이 영상으로 연습하는 방법
- 먼저 말하지 않고 영상을 끝까지 듣고 모르는 단어를 적어 둡니다.
- 0.75배속으로 한 문장씩 섀도잉을 시작하고, 익숙해지면 보통 속도로 돌아갑니다.
- 자신의 목소리를 녹음해 원본과 비교하고, pointer, programmer, edit 같은 단어에 특히 주의합니다.
이 영상의 문법
화자가 가장 많이 쓰는 문형을 영상 속 실제 표현과 함께 정리했습니다.
| 문형 | 영상 속 표현 |
|---|---|
| 수동태 be + 과거분사 — 누가 하는지보다 무슨 일이 일어나는지에 초점 | been asked · is set · is placed |
| 현재완료 have/has + 과거분사 — 과거의 일이 지금도 관련이 있을 때 | I've laid · I've just created · we've come |
| 관계절 who / which + 절 — 사람이나 사물에 대한 추가 정보 | variable, which is · name which is |
쉐도잉이란? 영어 실력을 빠르게 키우는 과학적 방법
쉐도잉(Shadowing)은 원래 전문 통역사 훈련을 위해 개발된 언어 학습 기법으로, 다언어 학자인 Dr. Alexander Arguelles에 의해 대중화된 방법입니다. 핵심 원리는 간단하지만 매우 강력합니다: 원어민의 영어를 들으면서 1~2초의 짧은 지연으로 즉시 소리 내어 따라 말하는 것——마치 '그림자(shadow)'처럼 화자를 따라가는 것입니다. 문법 공부나 수동적인 청취와 달리, 쉐도잉은 뇌와 입 근육이 동시에 실시간으로 영어를 처리하고 재현하도록 훈련합니다. 연구에 따르면 이 방법은 발음 정확도, 억양, 리듬, 연음, 청취력, 말하기 유창성을 크게 향상시킵니다. IELTS 스피킹 준비와 자연스러운 영어 소통을 원하는 분들에게 특히 효과적입니다.