date_operator.cpp

/*
设计一个日期类Date,，要求：
（1）包含年(year)、月(month)和日(day)私有数据成员。
（2）包含构造函数，重载关于一日期加上天数的加法运算符+、重载关于一日期减去天数的减加运算符-、重载输出运算符<<与输入运算符>>等。
*/
#include <iostream>
using namespace std;

class Time {
  friend ostream &operator<<(ostream &, Time &);
  friend istream &operator>>(istream &, Time &);

 private:
  int hour, minute, second;

 public:
  Time(int h = 1, int m = 1, int s = 1) {
    hour = (h >= 0 && h <= 23) ? h : 0;
    minute = (m >= 0 && m <= 59) ? m : 0;
    second = (s >= 0 && s <= 59) ? s : 0;
  }
  Time operator+(Time &);
  Time operator-(Time &);
  int getHour() { return hour; }
  int getMinute() { return minute; }
  int getSecond() { return second; }
};
Time Time::operator+(Time &t1) {
  this->hour += t1.hour;
  this->minute += t1.minute;
  this->second += t1.second;
}

ostream &operator<<(ostream &out, Time &t) {
  out << t.hour << ":" << t.minute << ":" << t.second;
  return out;
}

int main() {
  Time t1(20, 20, 20);
  Time t2(1, 1, 1);
  cout << t1 + t2;
}
/**
 * clang的报错
 Start
prog.cc:84:1: warning: control may reach end of non-void function
[-Wreturn-type]
}
^
prog.cc:91:1: warning: control may reach end of non-void function
[-Wreturn-type]
}
^
prog.cc:29:11: warning: unused variable 'days' [-Wunused-const-variable]
const int days[]= {0,31,28,31,30,31,30,31,31,30,31,30,31};
          ^
3 warnings generated.
/tmp/prog-5c8f64.o: In function `Date::endofmonth(int) const':
prog.cc:(.text+0xdc): undefined reference to `Date::days'
/tmp/prog-5c8f64.o: In function `Date::decrement1()':
prog.cc:(.text+0x155): undefined reference to `Date::days'
clang-8: error: linker command failed with exit code 1 (use -v to see
invocation)
1
Finish
 */