What is the output and explain this code in correct way ...

Question

sizeof

Answer 1

It's returning you the size value in BYTES.

Answer 2

In pure C and with some compiler, undefined functions will be cast to type int (*)(...) so there will be no error and the size of what it is returned (which is just an integer uninitialized) is 4 as integers are 4 bytes like @Jamie said
And yes, @Jamie pinpointed two biiig errors

Answer 3

#include<studio.h>

main
{

int a;
a=sizeof( printed(""););

printf("%d",a);

}

Answer 4

why answer is 4 ?????

Answer 5

That code won't run, compiler error...

But 4 bytes is an int size (int size is *not* ever guaranteed). Memory addresses are 4 bytes IIRC on 32bit systems. Whatever code you had has been copied wrong though. I mean line 1 says "studio.h", and it degrades from there. No return or args for main? And ;); is meaningless.