PracticeDev/study_cpp/cpp_primer_source_code/Chapter 15/tv.h

50 lines
1.5 KiB
C++

// tv.h -- Tv and Remote classes
#ifndef TV_H_
#define TV_H_
class Tv
{
public:
friend class Remote; // Remote can access Tv private parts
enum {Off, On};
enum {MinVal,MaxVal = 20};
enum {Antenna, Cable};
enum {TV, DVD};
Tv(int s = Off, int mc = 125) : state(s), volume(5),
maxchannel(mc), channel(2), mode(Cable), input(TV) {}
void onoff() {state = (state == On)? Off : On;}
bool ison() const {return state == On;}
bool volup();
bool voldown();
void chanup();
void chandown();
void set_mode() {mode = (mode == Antenna)? Cable : Antenna;}
void set_input() {input = (input == TV)? DVD : TV;}
void settings() const; // display all settings
private:
int state; // on or off
int volume; // assumed to be digitized
int maxchannel; // maximum number of channels
int channel; // current channel setting
int mode; // broadcast or cable
int input; // TV or DVD
};
class Remote
{
private:
int mode; // controls TV or DVD
public:
Remote(int m = Tv::TV) : mode(m) {}
bool volup(Tv & t) { return t.volup();}
bool voldown(Tv & t) { return t.voldown();}
void onoff(Tv & t) { t.onoff(); }
void chanup(Tv & t) {t.chanup();}
void chandown(Tv & t) {t.chandown();}
void set_chan(Tv & t, int c) {t.channel = c;}
void set_mode(Tv & t) {t.set_mode();}
void set_input(Tv & t) {t.set_input();}
};
#endif