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我是 C++ 和面向对象编程的新手,所以请耐心等待这个问题。我正在编写一个日期程序,该程序确定您输入的日期是否是闰年,计算两个日期之间的长度等等。这是我的代码。它有一个头文件 Date.h,以及两个源文件 Date.cpp 和 main.cpp:

日期.h

#include <iostream>
using namespace std;
class Date {
private:
static const int month_nb;
static const unsigned char month_days[];
static const unsigned char month_daysLeap[];
protected:
static bool testLeap(const int year_);
bool isLeap;
int year;
int month;
int day;
public:


Date(const int month_,const int day_,const int year_);


~Date(){};


int get_month() const {return month;}
int get_day() const {return day;}
int get_year() const {return year;}


void set_month(int m){month = m;}
void set_day(int d){day = d;}
void set_year(int y){year = y;}


bool testLeap() const;
void out() const;
bool testValid() const;
int operator-(const Date & date) const;
static int Julian(const Date & date1,const Date & date2);
static double CountACT_365(const Date & date1,const Date & date2);
static int Count30_360L(const Date & date1,const Date & date2);
static double Count30_360(const Date & date1,const Date & date2);
double CountACT_365(const Date & date) const;
int Count30_360L(const Date & date) const;
double Count30_360(const Date & date) const;
};
inline bool operator==(const Date& d1,const Date& d2)
{
return d1.get_month()==d2.get_month()
&& d1.get_day()==d2.get_day() && d1.get_year()==d2.get_year();
}
ostream& operator<<(ostream& os,const Date& d);

日期.cpp

#include <iostream>
#include "Date.h"
using namespace std;
const int Date::month_nb = 12;
const unsigned char Date::month_days[] = {31,28,31,30,31,30,31,31,30,31,30,31};
const unsigned char Date::month_daysLeap[] = {31,29,31,30,31,30,31,31,30,31,30,31};
Date::Date(const int month_, const int day_, const int year_)
{
year = year_; month = month_; day = day_;
isLeap = testLeap();
}
bool Date::testLeap(const int year_)
{
//if the year is not a multiple of 4, this is not a leap year
if(year_ % 4 != 0) return false;
//if the year is a multiple of 100, this is not a leap year,
//except if it is a multiple of 400.
if(year_ % 100 == 0) {
return year_ % 400 == 0;
}
return true;
}
bool Date::testLeap() const {
return testLeap(year);
}
void Date::out() const
{
cout << (int)month <<"/"<< (int)day <<"/"<< year << endl;
}
bool Date::testValid() const {
return (1 <= month && month <= month_nb && 1 <= day
&& ((isLeap && day <= month_daysLeap[month-1])
|| (!isLeap && day <= month_days[month-1])));
}
ostream& operator<<(ostream& os,const Date& d) {
return os<<d.get_month()<<'/'<<d.get_day()<<'/'<<d.get_year();
}

主文件

 #include <iostream>
#include "Date.h"
using namespace std;
int Count30_360L(Date date1, Date date2) {
return 360 * (int) (date2.get_year() - date1.get_year())
+ 30 * (int) (date2.get_month() - date1.get_month())
+ (date2.get_day() - date1.get_day());
}
double Count30_360(Date date1, Date date2) {
return (double) Count30_360L(date1, date2) / 360.0;
}
int main() {

    Date SBday = Date(8,24,1971);
    Date CBday = Date(9,28,1996);
    cout <<"Time elapsed " << CBday - SBday<<endl;
    cout << "Q: was 8/24/1971 in a leap year? A: "<<SBday.testLeap()<<endl;
    cout <<"Count30_360L(SBday,CBday) = "<< Count30_360L(SBday,CBday)<<endl;
    cout <<"Count30_360(SBday,CBday) = "<< Count30_360(SBday,CBday)<<endl;
    cout <<"CountACT_365(SBday,CBday) = "<< Count30_360L(SBday,CBday)<<endl;
    cout <<"CBday.Count30_360L(SBday) = "<< CBday.Count30_360L(SBday)<<endl;
    cout <<"CBday.Count30_360(SBday) = "<< CBday.Count30_360(SBday)<<endl;
    return 0;
    }

我收到以下错误消息:

g++ -static-libgcc -static-libstdc++ -o HW1_2.exe main.o Date.o

main.o:在函数“main”中:

...Debug/../main.cpp:24:未定义对“Date::operator-(Date const&) const”的引用

...Debug/../main.cpp:29:未定义对“Date::Count30_360L(Date const&) const”的引用

...Debug/../main.cpp:30: 未定义引用`Date::Count30_360(Date const&) const'

谁能帮帮我?谢谢!

4

1 回答 1

1
  • ...Debug/../main.cpp:24:未定义对“Date::operator-(Date const&) const”的引用

int operator-(const Date & date) const;在 Date.h 中声明但从未定义它。

  • ...Debug/../main.cpp:29:未定义对“Date::Count30_360L(Date const&) const”的引用

您声明int Count30_360L(const Date & date) const;但没有定义它(您确实定义了一个自由函数int Count30_360L(Date date1, Date date2))。

  • ...Debug/../main.cpp:30: 未定义引用`Date::Count30_360(Date const&) const'

同样,您double Count30_360(const Date & date) const;在 Data.h 中声明但从未定义它(但确实定义了一个自由函数double Count30_360(Date date1, Date date2))。

这些函数都在中引用main()

  • Bday - SBday
  • CBday.Count30_360L(SBday)
  • CBday.Count30_360(SBday)

您需要定义这些Date::成员函数(在 Date.cpp 中)。

还:

using namespace std;

这在头文件中不是一个好主意。请参阅为什么“使用命名空间标准”被认为是不好的做法?

如果你缩进你的代码,它也会极大地提高可读性。

于 2013-02-16T04:07:44.077 回答