typedef

typedef in C++

The typedef keyword in C++ is used for aliasing existing data types, user-defined data types, and pointers to a more meaningful name.

https://www.geeksforgeeks.org/cpp/typedef-in-cpp/

typedef unsigned long ulong;

// Syntax: typedef return_type (*alias_name)(parameter_types); typedef int (*MathFunc)(int, int);

Using

• "using" for namespaces
• "using" for inheritance
• "using" for aliasing:
• "using" for directives:

https://www.geeksforgeeks.org/cpp/using-keyword-in-cpp-stl/ https://www.youtube.com/watch?v=DBXkDAn8mps&list=WL&index=2

Difference between 'struct' and 'typedef struct' in C++ program?

https://www.tutorialspoint.com/article/difference-between-struct-and-typedef-struct-in-cplusplus-program