If a POD is wrapped inside a class, does it give the same effect?

Question

Following are 2 different interpretations:

char c;  // 1
struct MyChar { char c; };  // 2

If I do new MyChar[100], will it allocate 100 bytes in all platform ? Adding non-virtual constructor/destructor and/or operators will make any effect on the size of MyChar ?

Answer 1

MyChar may have unnamed padding bytes after c, so no, it isn't guaranteed that sizeof(MyChar) is 1.

Answer 2

On MSVC, you can use:

#pragma pack(1)
struct MyChar 
{ 
    char c; 
}; 

// Restore
#pragma pack()