Why can't we initialize members inside a structure?

Question

Why can't we initialize members inside a structure ?

example:

struct s {    int i = 10; }; 

Answer 1

If you want to initialize non-static members in struct declaration:

In C++ (not C), structs are almost synonymous to classes and can have members initialized in the constructor.

struct s {     int i;      s(): i(10)     {     } }; 

If you want to initialize an instance:

In C or C++:

struct s {     int i; };  ...  struct s s_instance = { 10 }; 

C99 also has a feature called designated initializers:

struct s {     int i; };  ...  struct s s_instance = {     .i = 10, }; 

There is also a GNU C extension which is very similar to C99 designated initializers, but it's better to use something more portable:

struct s s_instance = {     i: 10, };