Code: #include<iostream> using namespace std; class A { int a,b; A obj; }; main() { cout<< " making of the object \n"; A allo; cout << "Object completed develpoped\n"; cout << sizeof(A); cout << "now the size of object\n"; cout << sizeof(allo); } When I compiled this code it gives the error I . e. incomplete type is not allowed.............but when I put static Such as Code: #include<iostream> using namespace std; class A { int a,b; static A obj; }; main() { cout<< " making of the object \n"; A allo; cout << "Object completed develpoped\n"; cout << sizeof(A); cout << "now the size of object\n"; cout << sizeof(allo); } It compiles without error giving the output as 8 in cout << sizeof(A); and the same 8 also in cout << sizeof(allo); Can somebody throw some light on the behavior of static object in its own class.
When its non static you are creating a cycle where the object has an object within itself as a member which is practically impossible to have but when it becomes static its equivalent to global object and so compiler does not give any error.
I'll add one thing that,- just declare the class as:- class A { int a,b; A *obj; }; Your problem will be solved. Otherwise, it becomes a recursive definition, which is not allowed. You can surely have a self-referencing pointer.
