Hello
   Your program should change to this style

#include <iostream.h>

class myBaseClass
{
public:
    myBaseClass(int , int);
    void print();

private:
    int x;
    int y;
};

// derived class
class myDerivedClass:public myBaseClass
{
public:
    myDerivedClass(int x, int y):myBaseClass(x, y){ //IZRAILEVICH1 revised here
    a=x;
    b=y;
    }
    void print();

private:
    int a;
    int b;
};

// base class implementation
myBaseClass :: myBaseClass(int param1, int param2)
{
    x = param1;
    y = param2;
}
void myDerivedClass :: print() // Added by me
{
    cout<<a<<" "<<b<<endl;
}

void myBaseClass :: print()
{
    cout<<x<<" "<<y<<endl;
}

// in main program


int main(int argc, char* argv[])
{
    printf("Hello World!\n");

    myDerivedClass derivedClass(5, 6);
    derivedClass.print();

    return 0;
}

// the output is :
    Hello World!
    5 6

zhangyanbo