C++ Variables and Data Types

Study Notes

A variable is a named storage location that holds a value.
In C++, a variable must be declared before it can be used.
A variable declaration consists of:
- Data type (e.g., int, char, float)
- Variable name (e.g., x, myVariable)
- Optional initialization value (e.g., = 5, = "hello")

Integers:
- int: whole numbers (e.g., 1, 2, 3)
- short: short integers (e.g., -32768 to 32767)
- long: long integers (e.g., -2147483648 to 2147483647)
- long long: extended long integers (e.g., -9223372036854775808 to 9223372036854775807)
Floating-Point Numbers:
- float: single-precision floating-point numbers (e.g., 3.14, -0.5)
- double: double-precision floating-point numbers (e.g., 3.14159, -0.50000)
- long double: extended-precision floating-point numbers
Characters:
- char: single character (e.g., 'a', 'Z', '?')
Boolean:
- bool: true or false values
Void:
- void: no value

Arrays:
- A collection of values of the same data type stored in contiguous memory locations.
- Declared using the square bracket notation (e.g., int myArray[5];)
Pointers:
- A variable that holds the memory address of another variable.
- Declared using the asterisk notation (e.g., int *ptr;)
References:
- An alias for an existing variable.
- Declared using the ampersand notation (e.g., int &ref = x;)

Note: This is a basic overview of C++ variables and data types. There are more advanced topics and nuances to explore in each area.

A variable is a named storage location that holds a value.
Variables must be declared before they can be used.
A variable declaration consists of a data type, variable name, and optional initialization value.

Integers:
- int: stores whole numbers (e.g., 1, 2, 3)
- short: stores short integers (e.g., -32768 to 32767)
- long: stores long integers (e.g., -2147483648 to 2147483647)
- long long: stores extended long integers (e.g., -9223372036854775808 to 9223372036854775807)
Floating-Point Numbers:
- float: stores single-precision floating-point numbers (e.g., 3.14, -0.5)
- double: stores double-precision floating-point numbers (e.g., 3.14159, -0.50000)
- long double: stores extended-precision floating-point numbers
Characters:
- char: stores single characters (e.g., 'a', 'Z', '?')
Boolean:
- bool: stores true or false values
Void:
- void: represents no value

Arrays:
- A collection of values of the same data type stored in contiguous memory locations.
- Declared using the square bracket notation (e.g., int myArray;).
Pointers:
- A variable that holds the memory address of another variable.
- Declared using the asterisk notation (e.g., int *ptr;).
References:
- An alias for an existing variable.
- Declared using the ampersand notation (e.g., int &ref = x;).

Integers:
- int: whole numbers (e.g. 1, 2, 3, etc.).
- short: short integer (e.g. -32768 to 32767).
- long: long integer (e.g. -2147483648 to 2147483647).
- long long: long long integer (e.g. -9223372036854775808 to 9223372036854775807).
Floating Point Numbers:
- float: single precision floating point (e.g. 3.14f).
- double: double precision floating point (e.g. 3.14).
- long double: extended precision floating point.
Characters:
- char: single character (e.g. 'a', 'B').
Boolean:
- bool: true or false value.

Can be initialized using the assignment operator (=).
Can also be initialized using direct initialization (e.g. int x(5);) or uniform initialization (e.g. int x{5};).
Good practice to initialize variables to avoid undefined behavior.