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+# Notes from Assignment 0 Videos
+
+## Tenets of OOP - https://www.freecodecamp.org/news/object-oriented-programming-concepts-21bb035f7260/
+
+- Four principles: **encanpsulation**, **abstraction**, **inheritance**, **polymorphism**
+
+### Encapsulation
+
+- When an object has private and public states/functions/methods
+- Example: A "Cat" class
+	- The class may have private fields, such as mood, hunger, and energy, and a private function `meow()`
+	- The class may have three public functions/methods
+		- `sleep()` will increase the object's energy and hunger
+		- `play()` will increase the object's mood, decrease its energy, and call the private `meow()` function
+		- `feed()` will decrease the object's hunger, increase its mood, and call the private `meow()` function
+
+### Abstraction
+
+- Concept that objects should only expose high-level mechanisms
+	- Natural extension of Encapsulation concept
+- Concept can be seen in real life, for example, a water cooler
+	- There is technology going on under the hood, but the end user only sees the lever to pull for water
+- Another example: smartphone
+	- Very complicated under the hood, but at a high level, there is only the home button, volume buttons, and charge input
+
+### Inheritance
+
+- Idea to combat the problem that often times, many objects are similar but differ slightly
+- Involves creating a parent class and a child class, which is derived from the parent
+- Example: We can have a Person class with a name and an email
+	- Then we can define a Teacher, which has all the fields from the Person class, plus an additional subject field
+		- We could create child classes from Teacher for Private Teacher and Public Teacher, which inherit the teacher fields with their own fields as well
+	- We could also define a Student, which has all the fields from the Person class, plus additional class and grades fields
+
+### Polymorphism
+
+- Creating a method in a parent that differs slightly between child classes that inherit this method
+- Example: There is a Shape parent class that has the method `CalculateArea()`
+	- The child classes are Triangle, Circle, and Rectangle, so each child class will have its own implementation of the `CalculateArea()` method
+
+---
+
+## C++ Data Types - https://www.softwaretestinghelp.com/data-types-in-cpp/
+
+- C++ supports two types of data
+	- Primitive/Standard data types
+	- User-defined data types
+
+### Primitve or Standard Data Types
+
+|Data Type     |C++ Keyword|Value Type                            |
+|--------------|-----------|--------------------------------------|
+|Character     |char       |Character (ASCII values)              |
+|Integer       |int        |Numeric whole numbers                 |
+|Floating point|float      |Decimal values with single precision  |
+|Decimal point |double     |Double precision floating point values|
+|Boolean       |bool       |True or false                         |
+|void          |void       |Valueless (no value)                  |
+|Wide character|wchar_t    |Character including Unicode strings   |
+
+- Primitves can also be modified in memory length using the following data modifiers:
+	- signed
+	- unsigned
+	- short
+	- long
+
+### User-defined Data Types
+
+- **Typedef**
+	- Sets an alias for another data type
+	- Example:
+		- `typedef int age;`
+		- The above code creates an alias `age` for the `int` data type
+
+- **Enumeration**
+	- Example:
+		- `enum daysOfWeek {Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday};`
+		- The above code creates a data type `daysOfWeek`. It recognizes all the above keywords (they are really aliases for integer values 0, 1, 2, etc.)
+	- Boolean is, in theory, an enumeration, since it recognizes the keywords true and false
+	- C++ example:
+
+```
+#include <iostream>
+using namespace std;
+
+enum daysOfWeek {Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday};
+
+int main(){
+	daysOfWeek today;
+	today = Thursday;
+	cout << "This is day " << today << " of the week";
+	return 0;
+}
+
+---
+
+//output:
+This is day 4 of the week
+```
+
+- **Class**
+	- Collection of objects
+	- Example: a Student class:
+
+```
+class student{
+	char *name;
+	int age;
+
+	public:
+		void printDetails(){
+			cout << "Name: " << name;
+			cout << "Age: " << age;
+		}
+}
+```
+
+- **Structure**
+	- A Structure is like a Class, but does not support methods (it can only have variables as its members)
+	- A Class is really just a structure that can support both variables and methods
+	- Example:
+
+```
+struct employee{
+	char name[50];
+	float salary;
+	int empId;
+};
+```
+
+## What C++ is and Why - https://www.youtube.com/watch?v=tbNe-3FXqFM
+
+### C++ in two lines
+
+- Direct map to hardware
+	- of infrastructure and fundamental data types
+	- Initially from C
+	- Future: use novel hardware better (caches, multicores, GPUs, FPGAs, SIMD, ...)
+
+- Zero-overhead abstraction
+	- Classes, inheritance, generic programming, ...
+	- Initially from Simula (where it wasn't zero overhead)
+
+### What really matters?
+
+- People
+- A programming language is a tool, not an end goal
+	- "Ordinary people" want great systems, not programming languages
+- Software developers want great tools
+	- not just programming language features
+
+### The onion principle
+
+- Management of complexity
+	- Make simple things simple!
+- Layer of abstraction
+	- The more layers you peel off the more you cry
+
+### An engineering approach
+
+- Principled and pragmatic design
+- Progress gradually guided by feedback
+- There are always many tradeoffs
+	- Choosing is hard
+- Design decisions have consequences
+	- Determine what kind of applications can be done well