c++非多继承产生的名字冲突问题

#include <iostream>
using namespace std;

class BASE1 {
public:    
    void show() { 
        cout << i << "\n"; 
    }
protected:    
    int i;
};

class BASE2 {
public:    
    void show() {
        cout << j << "\n"; 
    }
protected:
    int j;
};

class DERIVED: public BASE1, public BASE2 {
public:    
    void set(int x, int y) {
        i = x;   j = y;   
    }
};

int main() {    
    DERIVED obj;  // 声明一个派生类的对象
    obj.set(5, 7);    // set()是DERIVED类自身定义的
    obj.show();      // 存在二义性问题
    return 0;
}          

int main() {

    DERIVED obj; 
    obj.set(5, 7);
    obj.BASE1::show();
    obj.BASE2::show();

}

class DERIVED: public BASE1, public BASE2 {
public:
    void set(int x, int y) {
        i = x; j = y; 
    }
    void show() {
    cout << i << "\n"; 
    cout << j << "\n"; 
    }
};
int main() {

    DERIVED obj; // 声明一个派生类的对象
    obj.set(5, 7); // set()是DERIVED类自身定义的
    obj.show(); // 无二义性问题，调用的是DERIVED中新定义的版本
    obj.BASE1::show(); // 仍然可调用从BASE1继承下来show()
    obj.BASE2::show(); // 仍然可调用从BASE2继承下来show()
return
}