Answers for "nested structures"

how to put a struct in another struct C

struct B {  // <-- declare before
  int number;
};
struct A {
 int data;
 B b; // <--- declare data member of `B`
 };

Structure of Structs in c

struct [structure_tag]
{
    //member variable 1
    //member variable 2
    //member variable 3
    ...
}[structure_variables];