pointers - Call base class constructor after the derived class constructor in C++ -

consider following situation:

#include <iostream> using namespace std;  class {   public:     int y;     a(int &x) {         x = 2;         y = 1;     } };  class b : public {   public:     int *p;     b(int t) : a(*p) {} };  int main() {     b b(2);     return 0; } 

when constructor of b called, p has junk value. so, when *p passed a(), gives me segmentation fault. want initialize p = new int; before calling a(*p) - possible?

edit: interestingly, calling b's constructor without arguments didn't give segmentation fault.

the way introduce other struct:

class {   public:     int y;     a(int &x) {         x = 2;         y = 1;     } };  struct c {     explicit c(int* p) p(p) {}     int* p; }  class b : private c, public {   public:     b(int t) : c(new int), a(*p) {}     ~b() {delete p;}     b(const b&) = delete;     b& operator =(const b&) = delete; };