001 - Basics of Data Types

Fundamental Data Types

Integers

int - 4 bytes (but can be dependent on system architecture)

short int - smaller range than int
long int - larger range than int
long long int - even larger range than long int

Floating Point (Float, Double)

float - 4 bytes, single precision floating point 001 - Floating Point
double - 8 bytes, double precision floating point

Characters

char - 1 byte, stores the ASCII value of the letter, digit, or symbol

Boolean

bool - 1 byte

Derived Data Types

Arrays

Stores multiple values of the same data type in consecutive memory locations

Pointers

Store memory address of variable

References

Alternative way to share memory locations between variables. Create alias for another variable.

User Defined Data Types

Structures (Struct)

Used to store multiple data types under a single variable (like objects in javascript)

struct Person {
	std::string name;
	int age;
} 

Classes

More heavyweight version of structures where accessibility of member variables and functions is controlled. By default access is private.

class Person {
public:
	std::string name;
	int age;
	
	void printInfo() {
		std::cout << "Name: " << name << ", Age: " << age << std::endl;
	}
}

Unions

Stores different data types in same memory location.
The purpose is only to save memory and when you safely know that after having overwritten the data with what you need, you will not need the other types that are part of the union.
This is not meant to be some clever way to type conversion.

union Data {
	int num;
	char letter;
	float decimal;
};