Difference between revisions of "Intermediate C++ Game Programming Tutorial 1"
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| − | We've been using <code>int</code>s and <code>float</code>s and <code>bool</code>s this whole time, but have you ever wondered about a day in the life of a variable? In this video, we find that shit out, and so much more. We also learn about the cousins of <code>int</code> and <code>float</code>, adding to our arsenal basic data types we can use. What's the endgame you ask? This stuff is gonna help us understand pointers and strings, and it's just interesting shit. | + | We've been using <code>int</code>s and <code>float</code>s and <code>bool</code>s this whole time, but have you ever wondered about a day in the life of a variable? In this video, we find that shit out, and so much more. We also learn about the cousins of <code>int</code> and <code>float</code>, adding to our arsenal of basic data types we can use in our programs. What's the endgame you ask? This stuff is gonna help us understand pointers and strings, and it's just interesting shit. |
== Topics Covered == | == Topics Covered == | ||
| Line 11: | Line 11: | ||
== Video Timestamp Index == | == Video Timestamp Index == | ||
| − | [https://youtu.be/ | + | [https://youtu.be/CDVWSDt4tB4 Tutorial 1] |
| − | == Bonus Video: Red Pill [ | + | == Bonus Video: Red Pill [The Stack] == |
| − | The description of how | + | The description of how variables are organized in memory in Tutorial 1 is a simplified model that will help us understand memory and pointers; it is not 100% accurate. |
Chili had originally planned to teach the full details of how variables are allocated, explaining things like storage classes (stack, heap, static), the details of stack management and function stack frames, and exploration of the memory and machine instructions using the debugger. But then he realized that this amount of detail and complexity might be too much of a mind fuck for too many people, so he cut that content from Tutorial 1. | Chili had originally planned to teach the full details of how variables are allocated, explaining things like storage classes (stack, heap, static), the details of stack management and function stack frames, and exploration of the memory and machine instructions using the debugger. But then he realized that this amount of detail and complexity might be too much of a mind fuck for too many people, so he cut that content from Tutorial 1. | ||
| − | Since the video is already recorded, it will be released as optional content for people who are interested in the nitty-gritty details, but the keyword here is ''optional''; you are not required to know this content to continue on with the tutorials and it will not be referred to in the mainline tutorial series. | + | Since the video is already recorded, it will be released as optional content for people who are interested in the nitty-gritty details, but the keyword here is ''optional''; you are not required to know this content to continue on with the tutorials and it will not be referred to in the mainline tutorial series. It is, however, very interesting shit. |
| − | Video link: [https://youtu.be/ | + | Video link: [https://youtu.be/Cjx5C2I3UrA Red Pill - The Stack] |
== Homework == | == Homework == | ||
| − | This | + | This lesson's homework is to answer the following questions. When you think you have the answer, click "expand" to reveal the correct answer. |
1. In Microsoft Visual C++, what is the size in bytes of the following data types: <code>int</code>, <code>char</code>, <code>double</code>, <code>unsigned int</code>, <code>short</code>, <code>bool</code> | 1. In Microsoft Visual C++, what is the size in bytes of the following data types: <code>int</code>, <code>char</code>, <code>double</code>, <code>unsigned int</code>, <code>short</code>, <code>bool</code> | ||
| − | <div class="mw-collapsed mw-collapsible" | + | <div class="mw-collapsed mw-collapsible"><br /> |
<code>int</code>: 4<br /> | <code>int</code>: 4<br /> | ||
<code>char</code>: 1<br /> | <code>char</code>: 1<br /> | ||
<code>double</code>: 8<br /> | <code>double</code>: 8<br /> | ||
<code>unsigned int</code>: 4<br /> | <code>unsigned int</code>: 4<br /> | ||
| + | <code>short</code>: 2<br /> | ||
<code>bool</code>: 1 | <code>bool</code>: 1 | ||
| − | </div> | + | </div><br /> |
2. Make the following conversions: 01000111b -> dec, 11001111b -> hex, 10h -> dec, 7Ah -> bin, 193d -> bin | 2. Make the following conversions: 01000111b -> dec, 11001111b -> hex, 10h -> dec, 7Ah -> bin, 193d -> bin | ||
| − | <div class="mw-collapsed mw-collapsible" style="width:450px"> | + | <div class="mw-collapsed mw-collapsible" style="width:450px"><br /> |
01000111b -> dec: 71<br /> | 01000111b -> dec: 71<br /> | ||
11001111b -> hex: CF<br /> | 11001111b -> hex: CF<br /> | ||
| Line 41: | Line 42: | ||
7Ah -> bin: 01111010<br /> | 7Ah -> bin: 01111010<br /> | ||
193d -> bin: 11000001<br /> | 193d -> bin: 11000001<br /> | ||
| − | </div> | + | </div><br /> |
3. What is the size of this class in bytes with default compiler settings in Microsoft Visual C++, and how many of those bytes are padding:<br /> | 3. What is the size of this class in bytes with default compiler settings in Microsoft Visual C++, and how many of those bytes are padding:<br /> | ||
<syntaxhighlight lang="cpp" line="1" > | <syntaxhighlight lang="cpp" line="1" > | ||
| Line 53: | Line 54: | ||
}; | }; | ||
</syntaxhighlight> | </syntaxhighlight> | ||
| − | <div class="mw-collapsed mw-collapsible" style="width:450px"> | + | <div class="mw-collapsed mw-collapsible" style="width:450px"><br /> |
16 bytes (3 bytes padding) | 16 bytes (3 bytes padding) | ||
| − | </div> | + | </div><br /> |
4. Why is hexadecimal commonly used to represent values in programming?<br /> | 4. Why is hexadecimal commonly used to represent values in programming?<br /> | ||
| − | <div class="mw-collapsed mw-collapsible" style="width:450px"> | + | <div class="mw-collapsed mw-collapsible" style="width:450px"><br /> |
| − | It's easy to convert between hexadecimal and binary representations. | + | It's easy to convert between hexadecimal and binary representations, and hexadecimal takes far fewer digits to represent the same number. |
| − | </div> | + | </div><br /> |
| − | + | 5. When accessing variables in memory, often times many addition/multiplication operations must be performed to index into arrays or access elements of classes/structures. What is one way the compiler can optimize this for runtime performance?<br /> | |
| − | + | <div class="mw-collapsed mw-collapsible" style="width:450px"><br /> | |
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | ||
| − | <div class="mw-collapsed mw-collapsible" style="width:450px"> | + | |
If the indices and offsets are values that are known at compile time, the addresses will be pre-computed at compile time and not at runtime. | If the indices and offsets are values that are known at compile time, the addresses will be pre-computed at compile time and not at runtime. | ||
| − | </div> | + | </div><br /> |
== See also == | == See also == | ||
Latest revision as of 22:20, 13 October 2019
We've been using ints and floats and bools this whole time, but have you ever wondered about a day in the life of a variable? In this video, we find that shit out, and so much more. We also learn about the cousins of int and float, adding to our arsenal of basic data types we can use in our programs. What's the endgame you ask? This stuff is gonna help us understand pointers and strings, and it's just interesting shit.
Contents
Topics Covered
- The concept of memory (RAM)
- Binary and hexadecimal number systems
-
char,short,long long,double -
unsignedintegral types - The ranges and sizes of basic data types
- Layout of variables in memory
- Correspondence between C++ code and CPU operations
Video Timestamp Index
Bonus Video: Red Pill [The Stack]
The description of how variables are organized in memory in Tutorial 1 is a simplified model that will help us understand memory and pointers; it is not 100% accurate.
Chili had originally planned to teach the full details of how variables are allocated, explaining things like storage classes (stack, heap, static), the details of stack management and function stack frames, and exploration of the memory and machine instructions using the debugger. But then he realized that this amount of detail and complexity might be too much of a mind fuck for too many people, so he cut that content from Tutorial 1.
Since the video is already recorded, it will be released as optional content for people who are interested in the nitty-gritty details, but the keyword here is optional; you are not required to know this content to continue on with the tutorials and it will not be referred to in the mainline tutorial series. It is, however, very interesting shit.
Video link: Red Pill - The Stack
Homework
This lesson's homework is to answer the following questions. When you think you have the answer, click "expand" to reveal the correct answer.
1. In Microsoft Visual C++, what is the size in bytes of the following data types: int, char, double, unsigned int, short, bool
int: 4
char: 1
double: 8
unsigned int: 4
short: 2
bool: 1
2. Make the following conversions: 01000111b -> dec, 11001111b -> hex, 10h -> dec, 7Ah -> bin, 193d -> bin
01000111b -> dec: 71
11001111b -> hex: CF
10h -> dec: 16
7Ah -> bin: 01111010
193d -> bin: 11000001
3. What is the size of this class in bytes with default compiler settings in Microsoft Visual C++, and how many of those bytes are padding:
class Foo
{
public:
int a;
char b[3];
short c;
int d;
};16 bytes (3 bytes padding)
4. Why is hexadecimal commonly used to represent values in programming?
It's easy to convert between hexadecimal and binary representations, and hexadecimal takes far fewer digits to represent the same number.
5. When accessing variables in memory, often times many addition/multiplication operations must be performed to index into arrays or access elements of classes/structures. What is one way the compiler can optimize this for runtime performance?
If the indices and offsets are values that are known at compile time, the addresses will be pre-computed at compile time and not at runtime.
