Errors i can't understand

[c#_novice]

I use forward declaration to include class interface but get errors. Class Contract uses Class Date...

My Date.cpp

#include <time.h>
#include <iosfwd>

class Date						
{
public:

	Date() {
		SetDate( getCurrentTime() );
	}

	void SetDate(tm curr_tm)
	{
		day = curr_tm.tm_mday;
		month = curr_tm.tm_mon;
		year = curr_tm.tm_year;
		hour = curr_tm.tm_hour;
		minute = curr_tm.tm_min;
		local_dt = curr_tm;
	}

	static tm getCurrentTime()
	{
		time_t rawtime;
		tm* timeinfo;

		time( &rawtime );
		timeinfo = localtime ( &rawtime );

		return *timeinfo;
	}

	int getDay(){return day;}
	int getMonth(){return month;}
	int getYear(){return year;}
	int getHour(){return hour;}
	int getMinute(){return minute;}
	tm getLocalDT(){return local_dt;}

private:

	int day;
	int month;
	int year;
	int hour;
	int minute;
	tm local_dt;
};

Contract.h

// Class CONTRACT: Handles the rental contract details

#include <string>
#include <iosfwd>
//#include <iomanip>
//#include <fstream>
//#include <iostream>
//#include "Date.h"

class Date;

class Contract
{
public:
	
	Contract();

	void SetContractDetails(Date i, unsigned carR, const std::string& kms, float ratePD,
		unsigned lndrID, const std::string& contID, int days);

	void SetContractPeriod(Date i_dt, Date r_dt, int d, bool isLtd);
	void SetReturnDate();
	void DisplayContract();
	void Read(std::istream&, Contract&, bool);
	void Write(std::ostream&, bool);
	const std::string& getContractID() const;
	int getContractPeriod() const;
	float getRatePerDay() const;
	const std::string& getKmType() const;
	Date getIssueDate() const;
	Date getReturnDate() const;
	unsigned getLenderID() const;
	unsigned getCarReg() const;

private:
	std::string contractID;
	Date issued, returned;
	unsigned lenderID;
	unsigned carRegistration;
	int contractDays;
	std::string kmType;
	float dailyRate;
};
std::istream& operator >> (std::istream& in, Contract& rental);

Errors....

: error C2079: 'Contract::issued' uses undefined class 'Date'
: error C2079: 'Contract::returned' uses undefined class 'Date'
: error C2228: left of '.getDay' must have class/struct/union
1>        type is 'int'
: error C2228: left of '.getMonth' must have class/struct/union
1>        type is 'int'
: error C2228: left of '.getYear' must have class/struct/union
1>        type is 'int'
: error C2228: left of '.getHour' must have class/struct/union
1>        type is 'int'

etc...

[souldog]

you can only use forward declaration if the header file only includes pointers or references to the class that is forward declared.

Your header includes objects

Date issued, returned;

so forward declaration will not work

[thegrinch]

Hi!

1. Do you also have a file Date.h?
2. uncomment the line #include "date.h" in your Contract.h
3. Make sure to have a #pragma once on top of all your header files.

Regards
Oliver

[c#_novice]

you can only use forward declaration if the header file only includes pointers or references to the class that is forward declared.

Your header includes objects

Date issued, returned;

so forward declaration will not work

Oh! didn't know that, thanx...

[c#_novice]

Hi!

1. Do you also have a file Date.h?

Regards
Oliver

No, i made my date.h a date.cpp since there isn't much done there? Should i change it back since i need to include it?

[HighCommander4]

No, i made my date.h a date.cpp since there isn't much done there? Should i change it back since i need to include it?

It's the other way around: if your class methods are all very short, you can inline their implementations and put them in the header (.h) file. Then you include that header file weherever it's necessary, e.g. in Contract.h

So basically, just rename date.cpp back to date.h, and include date.h in Contract.h

[Lindley]

Oh! didn't know that, thanx...

The reason being that the compiler needs to know the size of the member object. The size of any pointer or reference is always equal to sizeof(void*), but an actual object's size is definition-dependent.