Global variable: All functions are defined outside of all functions, all functions of this file (irreversible), but cannot be used across files (redifact errors and unspecified mistakes must be in one, similar to non-repetitive exceptions: < )-> Global variables in separate files
Extern variable: You can declare within multiple functions of multiple files, but can only be initialized outside of a function of some and only one file (Extern Int J = 1), -> multiple files "Global" variable
Monitoring: Represents parameters of variable number, can operate the undefined parameters (i.e., in the omitted number), but unknown to identify the type: (Example: Void func (int i, ...)
