title
Copying and Copy Constructors in C++

description
Patreon ► https://patreon.com/thecherno Twitter ► https://twitter.com/thecherno Instagram ► https://instagram.com/thecherno Discord ► https://thecherno.com/discord In this video we're talking about copying in C++. Copying objects (and data) is commonly necessary in C++, and to properly facilitate that for our custom types, we need to add something called a copy constructor, which performs a deep copy of our object, if one is necessary. Something called a "(copy) assignment operator" is also sometimes necessary, but we'll talk about that in another video. Copying is not free however, and can slow down your program, so try and avoid it if possible. Series Playlist ► https://www.youtube.com/playlist?list=PLlrATfBNZ98dudnM48yfGUldqGD0S4FFb Thank you to the following Patreon supporters: - Samuel Egger - Dominic Pace Gear I use: ----------------- BEST laptop for programming! ► http://geni.us/pakTES My FAVOURITE keyboard for programming! ► http://geni.us/zNhB FAVOURITE monitors for programming! ► http://geni.us/Ig6KBq MAIN Camera ► http://geni.us/t6xyDRO MAIN Lens ► http://geni.us/xGoDWT Second Camera ► http://geni.us/CYUQ Microphone ► http://geni.us/wqO6g7K

detail
{'title': 'Copying and Copy Constructors in C++', 'heatmap': [{'end': 715.521, 'start': 700.812, 'weight': 0.825}, {'end': 889.739, 'start': 860.534, 'weight': 1}], 'summary': 'Explores c++ copying, emphasizing the importance of understanding and avoiding unnecessary copying for program efficiency, demonstrating the writing of a string class, delving into copying variables, memory addresses, memory management, and deep copy in c++, and promoting best practices for passing objects by const reference.', 'chapters': [{'end': 66.382, 'segs': [{'end': 66.382, 'src': 'embed', 'start': 19.402, 'weight': 0, 'content': [{'end': 22.845, 'text': 'A lot of the time we want to copy objects so that we can modify them in certain ways.', 'start': 19.402, 'duration': 3.443}, {'end': 24.747, 'text': 'But if we can avoid copying,', 'start': 22.925, 'duration': 1.822}, {'end': 30.993, 'text': 'if we can avoid unnecessary copying because we just want to read the value or we want to actually modify an existing object,', 'start': 24.747, 'duration': 6.246}, {'end': 33.876, 'text': 'we absolutely want to do that, because copying takes time.', 'start': 30.993, 'duration': 2.883}, {'end': 39.64, 'text': 'So copying can be both a really useful thing, that we actually need to make our program work the way that we want it to.', 'start': 34.056, 'duration': 5.584}, {'end': 46.105, 'text': 'but on the flip side, unnecessary copying is bad, and we want to avoid that as much as possible because it wastes performance.', 'start': 39.64, 'duration': 6.465}, {'end': 50.588, 'text': 'So understanding how copying actually works in C++ and how to get it to work,', 'start': 46.345, 'duration': 4.243}, {'end': 55.052, 'text': "and also how to avoid getting it to work or avoid copying when you don't want to copy,", 'start': 50.588, 'duration': 4.464}, {'end': 60.696, 'text': 'is very important to understanding the language and being able to write C++ code efficiently and correctly.', 'start': 55.052, 'duration': 5.644}, {'end': 64.54, 'text': "So to demonstrate this in an effective way, I'm actually going to write a full-on example.", 'start': 60.936, 'duration': 3.604}, {'end': 65.34, 'text': "We're going to write a class.", 'start': 64.56, 'duration': 0.78}, {'end': 66.382, 'text': "It's going to be a string class.", 'start': 65.361, 'duration': 1.021}], 'summary': 'Avoid unnecessary object copying to improve c++ program efficiency.', 'duration': 46.98, 'max_score': 19.402, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr3819402.jpg'}], 'start': 0.089, 'title': 'C++ copying and copy constructors', 'summary': 'Discusses the importance of understanding copying in c++, emphasizing the need to avoid unnecessary copying to improve program efficiency, as well as the significance of copy constructors in modifying objects. the demonstration of writing a string class is highlighted.', 'chapters': [{'end': 66.382, 'start': 0.089, 'title': 'C++ copying and copy constructors', 'summary': 'Discusses the importance of understanding copying in c++, emphasizing the need to avoid unnecessary copying to improve program efficiency, as well as the significance of copy constructors in modifying objects. the demonstration of writing a string class is highlighted.', 'duration': 66.293, 'highlights': ['Understanding how copying works in C++ and how to avoid unnecessary copying is crucial for writing efficient and correct C++ code.', 'The importance of avoiding unnecessary copying is emphasized due to its negative impact on performance.', 'The significance of copy constructors in modifying objects is highlighted as a key concept in the chapter.', 'Demonstration of writing a string class is mentioned as an effective way to understand the concept of copying in C++.']}], 'duration': 66.293, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr3889.jpg', 'highlights': ['Demonstration of writing a string class is mentioned as an effective way to understand the concept of copying in C++.', 'The significance of copy constructors in modifying objects is highlighted as a key concept in the chapter.', 'Understanding how copying works in C++ and how to avoid unnecessary copying is crucial for writing efficient and correct C++ code.', 'The importance of avoiding unnecessary copying is emphasized due to its negative impact on performance.']}, {'end': 230.711, 'segs': [{'end': 237.877, 'src': 'embed', 'start': 214.261, 'weight': 0, 'content': [{'end': 221.025, 'text': 'With the exception of references, whenever you write code where one variable is assigned another variable, you are always copying it.', 'start': 214.261, 'duration': 6.764}, {'end': 222.746, 'text': "It's just with the case of pointers.", 'start': 221.125, 'duration': 1.621}, {'end': 230.071, 'text': "you're copying the pointer that memory address the numeric memory address the number rather than the actual memory at the pointer,", 'start': 222.746, 'duration': 7.325}, {'end': 230.711, 'text': 'if that makes sense.', 'start': 230.071, 'duration': 0.64}, {'end': 237.877, 'text': "So with that in mind, let's write a string class and see about how we can make that copyable and what challenges we might face with that.", 'start': 230.831, 'duration': 7.046}], 'summary': 'Copying variables in code involves copying pointers to memory addresses rather than the actual memory itself. exploring challenges in making a string class copyable.', 'duration': 23.616, 'max_score': 214.261, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr38214261.jpg'}], 'start': 66.402, 'title': 'Copying variables and memory in programming', 'summary': 'Delves into the concept of copying variables in programming, detailing its functionality with primitive types, classes, and pointers, and highlighting the difference between copying values and memory addresses.', 'chapters': [{'end': 230.711, 'start': 66.402, 'title': 'Copying variables and memory in programming', 'summary': 'Discusses the concept of copying variables in programming, explaining how it works with primitive types, classes, and pointers, emphasizing the distinction between copying values and copying memory addresses.', 'duration': 164.309, 'highlights': ['The distinction between copying values and memory addresses is crucial in understanding how variables are copied in programming, with examples of primitive types, classes, and pointers.', 'The chapter explains that when assigning one variable to another, the underlying value is always copied, and with pointers, the memory address is copied rather than the actual memory at the pointer.', 'The concept of copying variables is illustrated through examples of primitive types, classes, and pointers, emphasizing the impact of copying on memory addresses and the values they point to.', 'The distinction between copying values and memory addresses is emphasized, with the explanation that references are exceptions to the general rule of copying variables.']}], 'duration': 164.309, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr3866402.jpg', 'highlights': ['The chapter explains that when assigning one variable to another, the underlying value is always copied, and with pointers, the memory address is copied rather than the actual memory at the pointer.', 'The concept of copying variables is illustrated through examples of primitive types, classes, and pointers, emphasizing the impact of copying on memory addresses and the values they point to.', 'The distinction between copying values and memory addresses is crucial in understanding how variables are copied in programming, with examples of primitive types, classes, and pointers.', 'The distinction between copying values and memory addresses is emphasized, with the explanation that references are exceptions to the general rule of copying variables.']}, {'end': 526.237, 'segs': [{'end': 274.789, 'src': 'embed', 'start': 248.286, 'weight': 0, 'content': [{'end': 254.671, 'text': "I'm just going to write a base kind of string class implementation that is using just the raw metal kind of C++ features.", 'start': 248.286, 'duration': 6.385}, {'end': 260.616, 'text': "And that's necessary because if I start using modern, modern kind of c++ features to write this class,", 'start': 254.691, 'duration': 5.925}, {'end': 266.882, 'text': "then it is actually going to automate a lot of this stuff for me and in this case it's not going to demonstrate my point about copying very well.", 'start': 260.616, 'duration': 6.266}, {'end': 267.803, 'text': 'so just keep that in mind.', 'start': 266.882, 'duration': 0.921}, {'end': 274.789, 'text': "this isn't how i would necessarily write a string class nowadays, but it is a way to do it and it's going to be a kind of nice, bare metal way,", 'start': 267.803, 'duration': 6.986}], 'summary': 'Creating a basic string class using raw c++ features to avoid automation and demonstrate manual copying.', 'duration': 26.503, 'max_score': 248.286, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr38248286.jpg'}, {'end': 336.205, 'src': 'embed', 'start': 304.874, 'weight': 1, 'content': [{'end': 310.096, 'text': "First thing we're going to do is calculate how long the string is so that we can copy the data from the string into our buffer.", 'start': 304.874, 'duration': 5.222}, {'end': 315.618, 'text': "So I'm just going to use a C function called strlen or string length to actually get the size of this string.", 'start': 310.296, 'duration': 5.322}, {'end': 318.019, 'text': "Now that I've got the size, I know how big I want my buffer.", 'start': 315.798, 'duration': 2.221}, {'end': 320.08, 'text': "It's going to be the size of the string.", 'start': 318.059, 'duration': 2.021}, {'end': 321.781, 'text': 'So new char m size.', 'start': 320.14, 'duration': 1.641}, {'end': 325.182, 'text': 'Now we actually have to allow for the null termination character as well.', 'start': 322.381, 'duration': 2.801}, {'end': 329.343, 'text': "So this should be plus one, but I'm deliberately not going to write that so that you guys can see what happens.", 'start': 325.202, 'duration': 4.141}, {'end': 336.205, 'text': 'So the next step is going to be to copy the value from this pointer into our actual buffer so that our buffer is populated with all of our characters.', 'start': 329.543, 'duration': 6.662}], 'summary': 'Using strlen to determine string size, copying data into buffer.', 'duration': 31.331, 'max_score': 304.874, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr38304874.jpg'}, {'end': 393.787, 'src': 'embed', 'start': 368, 'weight': 2, 'content': [{'end': 374.322, 'text': "keep that in mind, but let's write something that can at least print our string and something that we'll be able to use to print our string.", 'start': 368, 'duration': 6.322}, {'end': 376.943, 'text': 'So I want to be able to use this with standard cout.', 'start': 374.482, 'duration': 2.461}, {'end': 380.484, 'text': "So what I'm going to do is write an overload for that operator.", 'start': 377.143, 'duration': 3.341}, {'end': 389.106, 'text': "So we'll write std output stream operator shift left std output stream stream our string class.", 'start': 380.504, 'duration': 8.602}, {'end': 391.047, 'text': 'So this will be a const string reference.', 'start': 389.126, 'duration': 1.921}, {'end': 393.787, 'text': 'string, this is going to return our stream.', 'start': 391.827, 'duration': 1.96}], 'summary': 'Write an overload for the standard output stream operator to print strings.', 'duration': 25.787, 'max_score': 368, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr38368000.jpg'}, {'end': 472.307, 'src': 'embed', 'start': 445.141, 'weight': 3, 'content': [{'end': 450.242, 'text': "You can see it's accompanied by a lot of other random characters because we don't have that null termination character.", 'start': 445.141, 'duration': 5.101}, {'end': 451.802, 'text': "So let's go ahead and add that in.", 'start': 450.262, 'duration': 1.54}, {'end': 456.403, 'text': "The way I'm going to do that is just when I allocate the buffer, I'm going to do msize plus one.", 'start': 452.102, 'duration': 4.301}, {'end': 461.744, 'text': "You could also use string copy, which we're not going to talk about for now, but I'm just going to allocate msize plus one to make room for that.", 'start': 456.443, 'duration': 5.301}, {'end': 465.204, 'text': 'We know that this string does have a null termination character.', 'start': 462.364, 'duration': 2.84}, {'end': 472.307, 'text': 'So, to make this easy, I could write code like this, which kind of seems to copy over the length of this If I hit F5, this will work.', 'start': 465.244, 'duration': 7.063}], 'summary': 'Adding null termination character to buffer allocation for msize plus one', 'duration': 27.166, 'max_score': 445.141, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr38445141.jpg'}, {'end': 502.351, 'src': 'embed', 'start': 478.073, 'weight': 4, 'content': [{'end': 485.441, 'text': "If we can't guarantee that, just to be a bit safer, I'm just going to set mbuffer msize here equal to zero, like this,", 'start': 478.073, 'duration': 7.368}, {'end': 488.063, 'text': 'manually adding my own null termination character at the end of this.', 'start': 485.441, 'duration': 2.622}, {'end': 490.286, 'text': 'Hit F5 and we should be good.', 'start': 488.424, 'duration': 1.862}, {'end': 491.407, 'text': 'And you can see that we are.', 'start': 490.506, 'duration': 0.901}, {'end': 493.448, 'text': "We're finally writing some actual code in this series.", 'start': 491.527, 'duration': 1.921}, {'end': 494.208, 'text': 'Really excited about that.', 'start': 493.468, 'duration': 0.74}, {'end': 495.268, 'text': "Hope I'm not going too fast.", 'start': 494.248, 'duration': 1.02}, {'end': 496.369, 'text': "I'm kind of trying to rush through this.", 'start': 495.308, 'duration': 1.061}, {'end': 498.189, 'text': 'This is mostly basic kind of.', 'start': 496.689, 'duration': 1.5}, {'end': 502.351, 'text': 'this is me kind of setting up the string class so that I can actually show you the copying, which is what this video is about.', 'start': 498.189, 'duration': 4.162}], 'summary': 'Setting mbuffer msize to zero for safer null termination, writing code to demonstrate string copying.', 'duration': 24.278, 'max_score': 478.073, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr38478073.jpg'}], 'start': 230.831, 'title': 'C++ string class implementation and output operator overloading', 'summary': 'Discusses the implementation of a basic c++ string class using raw c++ features, including creating a string, calculating its size, and copying its value. it also covers overloading the output stream operator for the string class, enabling the printing of the cherno string and ensuring its proper null termination.', 'chapters': [{'end': 368, 'start': 230.831, 'title': 'C++ string class implementation', 'summary': 'Discusses the implementation of a basic c++ string class using raw c++ features, explaining the process of creating a string, calculating its size, and copying its value into a buffer.', 'duration': 137.169, 'highlights': ['The chapter discusses the implementation of a basic C++ string class using raw C++ features The speaker explains the process of creating a string class in a primitive C++ way, avoiding modern features like std vector or smart pointers.', 'Explaining the process of creating a string, calculating its size, and copying its value into a buffer The speaker demonstrates the process of calculating the size of the string using the strlen function, allocating memory for the buffer, and copying the value using memcpy.']}, {'end': 526.237, 'start': 368, 'title': 'Overloading output operator for string class', 'summary': 'Discusses overloading the output stream operator for the string class, demonstrating the process of creating a null-terminated string, and ensuring its proper null termination, enabling the printing of the cherno string.', 'duration': 158.237, 'highlights': ['The process of overloading the output stream operator (<<) for the string class is demonstrated, allowing the Cherno string to be printed using standard cout.', 'The method of creating a null-terminated string by allocating msize plus one to include the null termination character is explained.', 'The importance of ensuring proper null termination by manually setting mbuffer msize to zero to avoid potential issues is highlighted.', "The recommendation to join The Cherno's Discord server for further clarifications and discussions regarding the content is provided."]}], 'duration': 295.406, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr38230831.jpg', 'highlights': ['The chapter discusses the implementation of a basic C++ string class using raw C++ features.', 'Explaining the process of creating a string, calculating its size, and copying its value into a buffer.', 'The process of overloading the output stream operator (<<) for the string class is demonstrated.', 'The method of creating a null-terminated string by allocating msize plus one to include the null termination character is explained.', 'The importance of ensuring proper null termination by manually setting mbuffer msize to zero to avoid potential issues is highlighted.']}, {'end': 942.328, 'segs': [{'end': 559.558, 'src': 'embed', 'start': 526.297, 'weight': 2, 'content': [{'end': 528.818, 'text': "Okay, so we've got a basic setup here and everything looks pretty good.", 'start': 526.297, 'duration': 2.521}, {'end': 531.298, 'text': "We've actually got a bit of a memory leak here that we should really fix.", 'start': 528.838, 'duration': 2.46}, {'end': 533.679, 'text': 'And that is when we allocate this new char array here.', 'start': 531.338, 'duration': 2.341}, {'end': 534.699, 'text': 'We never delete it.', 'start': 533.739, 'duration': 0.96}, {'end': 541.743, 'text': "if we use a smart point or a vector, we wouldn't need to, but since we're using the new keyword and we're allocating a raw array,", 'start': 535.439, 'duration': 6.304}, {'end': 546.066, 'text': 'we have to actually delete it over here by calling delete buffer in the destructor.', 'start': 541.743, 'duration': 4.323}, {'end': 546.986, 'text': 'okay, fantastic.', 'start': 546.066, 'duration': 0.92}, {'end': 551.429, 'text': "so if we launch this code, we'll just verify that our program terminates successfully, and you can see it does.", 'start': 546.986, 'duration': 4.443}, {'end': 553.15, 'text': "now let's try to copy this string.", 'start': 551.429, 'duration': 1.721}, {'end': 554.071, 'text': 'so the way.', 'start': 553.55, 'duration': 0.521}, {'end': 559.558, 'text': 'so in this scenario, maybe i want to print out this string and then later on i actually want to print.', 'start': 554.071, 'duration': 5.487}], 'summary': 'Memory leak detected, code fixed, program terminated successfully.', 'duration': 33.261, 'max_score': 526.297, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr38526297.jpg'}, {'end': 638.897, 'src': 'embed', 'start': 610.184, 'weight': 0, 'content': [{'end': 613.207, 'text': 'And it takes those values and it copies them into a new memory address.', 'start': 610.184, 'duration': 3.023}, {'end': 617.008, 'text': 'which contains this string, this second string of ours.', 'start': 613.607, 'duration': 3.401}, {'end': 617.888, 'text': "Now here's the problem.", 'start': 617.108, 'duration': 0.78}, {'end': 621.229, 'text': 'What we have now in memory is two strings.', 'start': 618.269, 'duration': 2.96}, {'end': 626.931, 'text': 'And since it did a direct copy, something called a shallow copy, what it did is it copied this pointer.', 'start': 621.55, 'duration': 5.381}, {'end': 632.333, 'text': 'So we have two strings in memory, which of course have the exact same chart pointer value.', 'start': 626.991, 'duration': 5.342}, {'end': 638.897, 'text': 'In other words, the memory address of this buffer is the same for both of these strings.', 'start': 632.893, 'duration': 6.004}], 'summary': 'Memory contains two strings with the same pointer value.', 'duration': 28.713, 'max_score': 610.184, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr38610184.jpg'}, {'end': 731.19, 'src': 'heatmap', 'start': 700.812, 'weight': 0.825, 'content': [{'end': 705.755, 'text': "we're just going to return and buffer at index to keep it nice and simple.", 'start': 700.812, 'duration': 4.943}, {'end': 706.895, 'text': 'okay, this works.', 'start': 705.755, 'duration': 1.14}, {'end': 709.057, 'text': "let's hit f5 and check this out.", 'start': 706.895, 'duration': 2.162}, {'end': 710.538, 'text': "they're both chano.", 'start': 709.057, 'duration': 1.481}, {'end': 711.758, 'text': 'so why?', 'start': 710.538, 'duration': 1.22}, {'end': 712.479, 'text': 'why is that happening?', 'start': 711.758, 'duration': 0.721}, {'end': 714.66, 'text': 'and we get, and of course we also get the crash.', 'start': 712.479, 'duration': 2.181}, {'end': 715.521, 'text': 'so why is this happening?', 'start': 714.66, 'duration': 0.861}, {'end': 717.562, 'text': "it looks like we've copied it, but we haven't.", 'start': 715.521, 'duration': 2.041}, {'end': 723.386, 'text': 'what we actually need to do is allocate a new char array to store the copied string.', 'start': 717.562, 'duration': 5.824}, {'end': 731.19, 'text': "Because what we're doing now is we're copying the pointer and what we have is two string objects pointing to the exact same buffer of memory.", 'start': 723.886, 'duration': 7.304}], 'summary': 'Copying pointer instead of allocating new char array causing crash.', 'duration': 30.378, 'max_score': 700.812, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr38700812.jpg'}, {'end': 891.88, 'src': 'heatmap', 'start': 860.534, 'weight': 1, 'content': [{'end': 864.516, 'text': 'mbuffer, other.mbuffer, and then msize, other.size.', 'start': 860.534, 'duration': 3.982}, {'end': 868.679, 'text': "Okay, that's pretty much, that is exactly what C++ kind of supplies us with.", 'start': 864.877, 'duration': 3.802}, {'end': 877.116, 'text': "So that's not going to cut it here because we don't just want to copy the pointer.", 'start': 873.795, 'duration': 3.321}, {'end': 879.397, 'text': 'We want to copy the memory at the pointer.', 'start': 877.436, 'duration': 1.961}, {'end': 884.378, 'text': "Now, if we decide that we don't want a copy constructor because we don't want to allow copying,", 'start': 879.897, 'duration': 4.481}, {'end': 886.959, 'text': 'we can just declare this copy constructor as equals delete.', 'start': 884.378, 'duration': 2.581}, {'end': 889.739, 'text': 'And you can see down over here, this code will not compile anymore.', 'start': 887.319, 'duration': 2.42}, {'end': 891.88, 'text': 'This is exactly what unique pointer does.', 'start': 890.059, 'duration': 1.821}], 'summary': 'C++ provides mbuffer, other.mbuffer, msize, other.size. unique pointer handles copying.', 'duration': 43.033, 'max_score': 860.534, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr38860534.jpg'}], 'start': 526.297, 'title': 'C++ memory management', 'summary': 'Discusses fixing a memory leak in c++ code by deallocating a char array using the delete keyword, avoiding memory crashes due to shallow copying, and implementing deep copying through a copy constructor to create unique memory addresses for string objects.', 'chapters': [{'end': 575.177, 'start': 526.297, 'title': 'Fixing memory leak in c++ code', 'summary': 'Discusses fixing a memory leak in c++ code by deallocating a char array using the delete keyword in the destructor, ensuring program termination, and verifying the correct functionality of string copying and manipulation.', 'duration': 48.88, 'highlights': ['The importance of fixing a memory leak in C++ code by deallocating a char array using the delete keyword in the destructor.', 'Verification of successful program termination after fixing the memory leak.', 'Demonstration of correct functionality in string copying and manipulation.']}, {'end': 942.328, 'start': 575.197, 'title': 'C++ memory management', 'summary': 'Discusses the pitfalls of shallow copying in c++ string class, leading to memory crashes due to sharing of memory addresses, and emphasizes the need for deep copying to create unique memory addresses for string objects. it also explains the implementation of a copy constructor to achieve deep copying.', 'duration': 367.131, 'highlights': ['The chapter explains how shallow copying in C++ string objects leads to memory crashes due to shared memory addresses, emphasizing the need for deep copying to create unique memory addresses for string objects.', 'It discusses the implementation of a copy constructor in C++ to achieve deep copying, providing a detailed example of how to allocate a new buffer and copy the memory from the other string object, ensuring unique memory addresses for each string object.', 'It also demonstrates the consequences of shallow copying by modifying the second string, highlighting that changes to one string affect the other due to shared memory addresses, ultimately leading to a crash.', 'The chapter also touches upon the possibility of disabling the copy constructor to prevent copying and mentions the similarity to the behavior of unique pointers in C++.']}], 'duration': 416.031, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr38526297.jpg', 'highlights': ['The chapter explains how shallow copying in C++ string objects leads to memory crashes due to shared memory addresses, emphasizing the need for deep copying to create unique memory addresses for string objects.', 'It discusses the implementation of a copy constructor in C++ to achieve deep copying, providing a detailed example of how to allocate a new buffer and copy the memory from the other string object, ensuring unique memory addresses for each string object.', 'The importance of fixing a memory leak in C++ code by deallocating a char array using the delete keyword in the destructor.', 'Verification of successful program termination after fixing the memory leak.', 'Demonstration of correct functionality in string copying and manipulation.', 'It also demonstrates the consequences of shallow copying by modifying the second string, highlighting that changes to one string affect the other due to shared memory addresses, ultimately leading to a crash.', 'The chapter also touches upon the possibility of disabling the copy constructor to prevent copying and mentions the similarity to the behavior of unique pointers in C++.']}, {'end': 1234.061, 'segs': [{'end': 1051.225, 'src': 'embed', 'start': 1016.905, 'weight': 0, 'content': [{'end': 1022.708, 'text': "What's actually happening is every time we copy a string, we allocate memory on the heap copy all that memory.", 'start': 1016.905, 'duration': 5.803}, {'end': 1024.449, 'text': 'And then at the end of it, we free it.', 'start': 1022.728, 'duration': 1.721}, {'end': 1025.97, 'text': "That's completely unnecessary.", 'start': 1024.509, 'duration': 1.461}, {'end': 1032.275, 'text': "What we actually wanna do is just pass the existing string into this print string function, because we know that we're not gonna need to copy.", 'start': 1026.29, 'duration': 5.985}, {'end': 1033.555, 'text': "We don't need another copy of it.", 'start': 1032.335, 'duration': 1.22}, {'end': 1035.517, 'text': 'We can just reference the existing one.', 'start': 1033.596, 'duration': 1.921}, {'end': 1039.7, 'text': 'And the way that we do that is by passing this by reference, which we can do by taking a reference here.', 'start': 1035.656, 'duration': 4.044}, {'end': 1043.801, 'text': 'Now, this class will actually not be modifying the string.', 'start': 1040.119, 'duration': 3.682}, {'end': 1047.303, 'text': 'So what we should do really is mark it as a const reference.', 'start': 1044.142, 'duration': 3.161}, {'end': 1051.225, 'text': "If we don't mark it as const, not only does that mean that we can actually edit this.", 'start': 1047.363, 'duration': 3.862}], 'summary': 'Avoid unnecessary memory allocation by passing string as const reference in print function.', 'duration': 34.32, 'max_score': 1016.905, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr381016905.jpg'}, {'end': 1133.176, 'src': 'embed', 'start': 1105.598, 'weight': 2, 'content': [{'end': 1109.024, 'text': "What I'm trying to tell you is always pass your objects by const reference.", 'start': 1105.598, 'duration': 3.426}, {'end': 1117.588, 'text': "Always. We'll talk about really kind of in-depth optimization about that in the future, because maybe in some situations actually might be faster to copy.", 'start': 1109.924, 'duration': 7.664}, {'end': 1124.171, 'text': 'but for all intents and purposes, especially on a basic level, always pass your objects by const reference,', 'start': 1117.588, 'duration': 6.583}, {'end': 1126.432, 'text': "because the function itself that you're writing.", 'start': 1124.171, 'duration': 2.261}, {'end': 1132.035, 'text': "you can decide if you want to copy in that function, but there's no reason for you just to be throwing around copies all the time.", 'start': 1126.432, 'duration': 5.603}, {'end': 1133.176, 'text': 'That slows your program down.', 'start': 1132.055, 'duration': 1.121}], 'summary': 'Pass objects by const reference to avoid slowing down the program.', 'duration': 27.578, 'max_score': 1105.598, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr381105598.jpg'}], 'start': 942.368, 'title': 'String copying and references', 'summary': 'Explores deep copy in c++ and the inefficiency of unnecessary string copying, emphasizing the need for passing strings by const reference to avoid unnecessary memory allocation and deallocation. it also explains best practices for passing objects by const reference in c++, promoting support through patreon for early access to episodes and a private discord channel.', 'chapters': [{'end': 1085.219, 'start': 942.368, 'title': 'String copying and references', 'summary': 'Explores the concept of deep copy in c++ and highlights the inefficiency of unnecessary string copying, emphasizing the need for passing strings by const reference to avoid unnecessary memory allocation and deallocation, with a demonstration of the impact on string copies when using a print function.', 'duration': 142.851, 'highlights': ['The inefficiency of unnecessary string copying is demonstrated, with three string copies happening when passing it into a function, showcasing the impact of unnecessary memory allocation and deallocation.', 'The need for passing strings by const reference to avoid unnecessary memory allocation and deallocation is emphasized, as it allows referencing the existing string without the need for another copy.', 'The concept of deep copy in C++ is explained, highlighting the process of allocating memory on the heap, copying all that memory, and then freeing it, which is deemed unnecessary.', 'The importance of marking the string as a const reference to prevent modification and to disallow passing temporary R values into the function is emphasized to optimize memory usage and prevent unintended string edits.']}, {'end': 1234.061, 'start': 1085.219, 'title': 'C++ copying best practices', 'summary': 'Explains the best practice of passing objects by const reference in c++, emphasizing its impact on program efficiency and the advantage of reducing unnecessary copies, while also promoting support through patreon for early access to episodes and a private discord channel.', 'duration': 148.842, 'highlights': ['Always pass objects in C++ by const reference to optimize program efficiency and reduce unnecessary copies. Optimizing program efficiency, reducing unnecessary copies', 'Support the series through Patreon for early access to episodes and a private Discord channel, ensuring more content creation. Support through Patreon, early access to episodes, private Discord channel']}], 'duration': 291.693, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/BvR1Pgzzr38/pics/BvR1Pgzzr38942368.jpg', 'highlights': ['The inefficiency of unnecessary string copying is demonstrated, with three string copies happening when passing it into a function, showcasing the impact of unnecessary memory allocation and deallocation.', 'The need for passing strings by const reference to avoid unnecessary memory allocation and deallocation is emphasized, as it allows referencing the existing string without the need for another copy.', 'Always pass objects in C++ by const reference to optimize program efficiency and reduce unnecessary copies.', 'The concept of deep copy in C++ is explained, highlighting the process of allocating memory on the heap, copying all that memory, and then freeing it, which is deemed unnecessary.']}], 'highlights': ['The importance of avoiding unnecessary copying is emphasized due to its negative impact on performance.', 'Understanding how copying works in C++ and how to avoid unnecessary copying is crucial for writing efficient and correct C++ code.', 'Demonstration of writing a string class is mentioned as an effective way to understand the concept of copying in C++.', 'The significance of copy constructors in modifying objects is highlighted as a key concept in the chapter.', 'The concept of deep copy in C++ is explained, highlighting the process of allocating memory on the heap, copying all that memory, and then freeing it, which is deemed unnecessary.', 'The need for passing strings by const reference to avoid unnecessary memory allocation and deallocation is emphasized, as it allows referencing the existing string without the need for another copy.', 'Always pass objects in C++ by const reference to optimize program efficiency and reduce unnecessary copies.', 'The inefficiency of unnecessary string copying is demonstrated, with three string copies happening when passing it into a function, showcasing the impact of unnecessary memory allocation and deallocation.', 'The chapter explains how shallow copying in C++ string objects leads to memory crashes due to shared memory addresses, emphasizing the need for deep copying to create unique memory addresses for string objects.', 'The distinction between copying values and memory addresses is emphasized, with the explanation that references are exceptions to the general rule of copying variables.', 'The chapter also touches upon the possibility of disabling the copy constructor to prevent copying and mentions the similarity to the behavior of unique pointers in C++.', 'The chapter discusses the implementation of a basic C++ string class using raw C++ features.', 'Explaining the process of creating a string, calculating its size, and copying its value into a buffer.', 'The process of overloading the output stream operator (<<) for the string class is demonstrated.', 'The method of creating a null-terminated string by allocating msize plus one to include the null termination character is explained.', 'The importance of ensuring proper null termination by manually setting mbuffer msize to zero to avoid potential issues is highlighted.', 'The chapter explains that when assigning one variable to another, the underlying value is always copied, and with pointers, the memory address is copied rather than the actual memory at the pointer.', 'The concept of copying variables is illustrated through examples of primitive types, classes, and pointers, emphasizing the impact of copying on memory addresses and the values they point to.', 'The distinction between copying values and memory addresses is crucial in understanding how variables are copied in programming, with examples of primitive types, classes, and pointers.', 'The chapter explains how shallow copying in C++ string objects leads to memory crashes due to shared memory addresses, emphasizing the need for deep copying to create unique memory addresses for string objects.', 'It discusses the implementation of a copy constructor in C++ to achieve deep copying, providing a detailed example of how to allocate a new buffer and copy the memory from the other string object, ensuring unique memory addresses for each string object.', 'The importance of fixing a memory leak in C++ code by deallocating a char array using the delete keyword in the destructor.', 'Verification of successful program termination after fixing the memory leak.', 'Demonstration of correct functionality in string copying and manipulation.', 'It also demonstrates the consequences of shallow copying by modifying the second string, highlighting that changes to one string affect the other due to shared memory addresses, ultimately leading to a crash.']}