c++ - How to prove that Copy Constructor is mandatory -

i have created class integer variable , pointer variable. after creating object , passed function. after returning function program not throwing exception

#include"iostream" using namespace std;  class {  public :      int i;      char *c;      void show();  };  void func(a obj);  int main() {      a;      a.i = 10;      a.c = "string";      cout << " before fun " << endl;      a.show();      cout << " going call func " << endl;      func(a);      cout << " after func " << endl;      a.show();      return 0;  }   void a::show() {     cout << " valuses in object " << << '\t' << c  << endl; }  void func(a aa) {            cout << " valuses in object " << aa.i << '\t' << aa.c  << endl;   } 

in func passing object (from main) , copied in aa (stack of func). after returning func if call show ( pointer c null of a), give me exception not happening . please me prove requirement of copy constructor

hide copy constructor. cause compilation error everywhere called implicitly.

class {  public :      int i;      char *c; private:     a(const a& _other); };