Thread: Invoking base class constructor

Hi
Please look this code

Code:

// constructors and derived classes
#include <iostream>
using namespace std;

class mother {
  public:
    mother ()
      { cout << "mother: no parameters\n"; }
    mother (int a)
      { cout << "mother: int parameter\n"; }
};

class daughter : public mother {
  public:
    daughter (int a)
      { cout << "daughter: int parameter\n\n"; }
};

class son : public mother {
  public:
    son (int a) : mother (a)
      { cout << "son: int parameter\n\n"; }
};

int main () {
  daughter cynthia (0);
  son daniel(0);
  
  return 0;
}

If i change that part:
son (int a) : mother (a)
{ cout << "son: int parameter\n\n"; }
with this:

Code:

class son : public mother {
  public:
	  son (int a): mother (a) ;
     };

son::son(int a) : mother (a)
{ cout << "son: int parameter\n\n"; };

It gives error.
Can't i write son (int a): mother (a) ; while declaring it.
If i want to invoke base class conts. must i write when defining conts.?
Is this rule?
Thanks...

The initialization list must appear only once when defining the function.

Hmm, Thank you for this information. Understood.

BTW, if this is more than just an example, son publicly inheriting from mother doesn't make a lot of sense. A son is not a mother. A son has a mother, so use composition (make mother a member variable). Private inheritance is another possibility but not really a good one.