c++ - Is typedef just a string replacement in code or somethings else?

Question

I was curious to know how exactly typedef works.

typedef struct example identifier;

identifier x;

In above statement is 'identifier' just replaced (somethings like string replacement) with 'struct example' in code? If no, what does typedef do here?

please enlighten!

Answer 1

No, it is not a string replacement - that would be macros. It creates an alias for the type.

typedefs are preferred over macros for custom types, in part because they can correctly encode pointer types.

typedef char *String_t;
#define String_d char *
String_t s1, s2;
String_d s3, s4;

s1, s2, and s3 are all declared as char *, but s4 is declared as a char, which is probably not the intention.