declaration does not declare anything : warning?

Question

#include 
#include 
#include 

int main()
{
    struct emp
    {
        struct address
        {
              int a;
             


        

Answer 1

The syntax of a structure definition is:

struct identifier {
    type member_name;

    // ...

};

If you add an identifier just after the closing curly brace, you're declaring a variable with that defined struct.

In your first example the compiler consider the address struct as member type. it's like if you writes:

struct identifier {

    type ; // No member name is specified
    type a1;

    // ...

}

But in the second example you specified the member name:

struct identifier {

    type a1; // Member name specified

    // ...

}

And here is an example of the warning: http://ideone.com/KrnYiE.