h----------------------
#ifndef DEMOCLASS_H
#define DEMOCLASS_H

#include <iostream>
using namespace std;

class DemoClass
{
public:
    DemoClass();
    void func(int);
    void func(char);
};

class DerivedClass:public DemoClass
{
 public:
     using DemoClass::func;
     void func(string);
};


#endif // DEMOCLASS_H


cpp---------------------------
#include "democlass.h"

DemoClass::DemoClass()
{
    cout<<"construct..."<<endl;
}

void DemoClass::func(int)
{
    cout<<"DemoClass func(int)..."<<endl;
}

void DemoClass::func(char)
{
    cout<<"DemoClass func(char)..."<<endl;
}

void DerivedClass::func(string)
{
    cout<<"DerivedClass func(string)..."<<endl;
}


main----------------------
#include <QCoreApplication>
#include "democlass.h"

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    DemoClass *demo;
    DerivedClass derived;
    demo = &derived;

    cout<<"...Demo object that point to Derived access func..."<<endl;
    demo->func(1);
    demo->func('a');

    cout<<endl<<"...derived object access func..."<<endl;
    derived.func(1);
    derived.func('a');
    derived.func("abc");
    return a.exec();
}



运行结果--------------------
construct...
...Demo object that point to Derived access func...
DemoClass func(int)...
DemoClass func(char)...

...derived object access func...
DemoClass func(int)...
DemoClass func(char)...
DerivedClass func(string)...