Some personal reading notes
variable
Initial value: When the object gets a specific value when it is created Default
initialization: The default initialization value of variables defined outside any function body is 0, and built-in type variables defined outside the function body will not be initialized
Declaration: Make the name Known to the program, the declaration specifies the type and name of the variable
Definition: responsible for creating the entity associated with the name
Basic built-in types
Signed signed: positive number, negative number, 0 (int, short, long, long long)
unsigned unsigned: means a number greater than or equal to 0
2.3 Composite types
Reference: A reference is not an object, but another name for an existing object. A reference can only be bound to an object, and cannot be bound to a literal value or the result of an expression
Pointer: The pointer itself is an object that allows copying and assignment, and it can point to several different objects successively during the lifetime of the pointer.
Define the pointer: basic data type * pointer name
2.5 Types of processing
literal constant
Each literal constant corresponds to a data type: the form and value of a literal constant determine its data type
Pointer literal: nullptr
Floating-point literals: represented as a decimal or scientific notation
String literal: actually an array of constant characters
The compiler adds a null character '\0' at the end of the string, so the actual length of the string literal is 1 more than its content
Decimal: By default, decimal integers are signed numbers
Octal:
Integers starting with 0 Hexadecimal: Integers starting with 0x or 0X