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Diffstat (limited to 'chapter14/clocks.cxx')
| -rw-r--r-- | chapter14/clocks.cxx | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/chapter14/clocks.cxx b/chapter14/clocks.cxx new file mode 100644 index 0000000..c3ed0ae --- /dev/null +++ b/chapter14/clocks.cxx @@ -0,0 +1,137 @@ +// FILE: clocks.cxx (part of the namespace main_savitch_14)
+// CLASSES IMPLEMENTED: clock, cuckoo_clock, clock24 (see clock.h)
+// INVARIANT for the clock ADT:
+// 1. The current hour is stored in my_hour, using 12-hour notation.
+// 2. The current minute is stored in my_minute.
+// 3. If the time is from midnight to 11:59 am (inclusive), then
+// my_morning is true; otherwise my_morning is false.
+
+#include <cassert>
+#include "clocks.h"
+
+namespace main_savitch_14
+{
+ clock::clock( )
+ {
+ my_hour = 12;
+ my_minute = 0;
+ my_morning = true;
+ }
+
+ void clock::set_time(int hour, int minute, bool morning)
+ // Library facilities used: cassert
+ {
+ assert(1 <= hour);
+ assert(hour <= 12);
+ assert(0 <= minute);
+ assert(minute <= 59);
+
+ my_hour = hour;
+ my_minute = minute;
+ my_morning = morning;
+ }
+
+ void clock::advance(int minutes)
+ {
+ const int MINUTES_IN_DAY = 24*60;
+ const int MINUTES_IN_HOUR = 60;
+
+ // Change the minutes so that 0 <= minutes < MINUTES_IN_DAY
+ if (minutes < 0)
+ minutes += MINUTES_IN_DAY * (1 - minutes/MINUTES_IN_DAY);
+ if (minutes >= MINUTES_IN_DAY)
+ minutes -= MINUTES_IN_DAY * (minutes/MINUTES_IN_DAY);
+
+ // Advance the clock any full hours
+ while (minutes > 60)
+ {
+ minutes -= MINUTES_IN_HOUR;
+ my_hour++;
+ if (my_hour == 12)
+ my_morning = !my_morning;
+ if (my_hour == 13)
+ my_hour = 1;
+ }
+
+ // Advance any remaining minutes
+ my_minute += minutes;
+ if (my_minute >= MINUTES_IN_HOUR)
+ {
+ my_minute -= MINUTES_IN_HOUR;
+ my_hour++;
+ if (my_hour == 12)
+ my_morning = !my_morning;
+ if (my_hour == 13)
+ my_hour = 1;
+ }
+ }
+
+ int clock::get_hour( ) const
+ {
+ return my_hour;
+ }
+
+ int clock::get_minute( ) const
+ {
+ return my_minute;
+ }
+
+ bool clock::is_morning( ) const
+ {
+ return my_morning;
+ }
+
+ bool cuckoo_clock::is_cuckooing( ) const
+ {
+ return (get_minute( ) == 0);
+ }
+
+ bool operator <(const clock& c1, const clock& c2)
+ {
+ // Check whether one is morning and the other is not
+ if (c1.is_morning( ) && !c2.is_morning( ))
+ return true;
+ else if (c2.is_morning( ) && !c1.is_morning( ))
+ return false;
+
+ // Check whether one is 12 o'clock and the other is not
+ else if ((c1.get_hour( ) == 12) && (c2.get_hour( ) != 12))
+ return true;
+ else if ((c2.get_hour( ) == 12) && (c1.get_hour( ) != 12))
+ return false;
+
+ // Check whether the hours are different from each other
+ else if (c1.get_hour( ) < c2.get_hour( ))
+ return true;
+ else if (c2.get_hour( ) < c1.get_hour( ))
+ return false;
+
+ // The hours are the same, so check the minutes
+ else if (c1.get_minute( ) < c2.get_minute( ))
+ return true;
+ else
+ return false;
+ }
+
+ int clock24::get_hour( ) const
+ {
+ int ordinary_hour;
+
+ ordinary_hour = clock::get_hour( );
+ if (is_morning( ))
+ {
+ if (ordinary_hour == 12)
+ return 0;
+ else
+ return ordinary_hour;
+ }
+ else
+ {
+ if (ordinary_hour == 12)
+ return 12;
+ else
+ return ordinary_hour + 12;
+ }
+ }
+
+}
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