example26.cpp

来自「Advanced Internet Programming Lecture 2 」· C++ 代码 · 共 52 行

nclude <iostream>
using namespace std;

class number {
protected:
  int val;
public:
  void setval(int i) { val = i; }

  // show() is a pure virtual function
  virtual void show() = 0;
};

class hextype : public number {
public:
  void show() {
    cout << hex << val << "\n";
  }
};

class dectype : public number {
public:
  void show() {
    cout << val << "\n";
  }
};

class octtype : public number {
public:
  void show() {
    cout << oct << val << "\n";
  }
};
nt main()
{
  dectype d;
  hextype h;
  octtype o;

  d.setval(20);
  d.show(); // displays 20 - decimal

  h.setval(20);
  h.show(); // displays 14 - hexadecimal

  o.setval(20);
  o.show();  // displays 24 - octal

  return 0;
}