Need to create an Entry.cpp file

[Lacy9265]

I need to create a entry.cpp file that will follow the functions listed in the entry.h file listed below. Could anyone help me create one?

  /** A class of entries to add to an array based implementation of the ADT dictionary*/

#pragma once

#ifndef ENTRY_
#define ENTRY_

template <class KeyType, class ValueType>

class Entry
{

private:
	KeyType key;
	ValueType value;

protected:
	void setKey(const KeyType& searchKey);

public:
	Entry();
	Entry(const KeyType& searchKey, const ValueType& newValue);
	ValueType getValue() const;
	KeyType getKey() const;
	void setValue(const ValueType& newValue);

	bool operator ==(const Entry<KeyType, ValueType>& rightHandValue) const;
	bool operator >(const Entry<KeyType, ValueType>& leftHandValue) const;

}; // end Entry

#include Entry.cpp

#endif  

[seeplus]

What part(s) are you having difficulty with? What part(s) have you done/tried?

[thmm]

Why do you need a .cpp file?
Code with templates is normally all in the header file.

[Lacy9265]

I'm confused on how I do the two bool operator and the getValue/getKey.

[seeplus]

So post what you have now. thmm is quite right. The function bodies for a templated class need to be in the same file as the class definition - but the .h file has an #include Entry.cpp. This would work, but isn't usually how it's done.

[Lacy9265]

I'm just following the code that is listed in my textbook. I need to use to this h file to create a entry.cpp file.

[Handy Andy]

Hello Lacy9265,

I realize that your book may say "Entry.cpp", but as a ".cpp" file it should be compiled as any ".cpp" would be as part of the whole solution/project.

Try using the extension of ".inl" or ".ipp". As a header file extension this should not compile as part of the project until you include it somewhere.

This would give you the ability to split the templated class into 2 files, yet make them as 1 at compile time.

I believe this should, but have not had a chance to test it yet.

Andy

[Lacy9265]

Hello Andy,

I have to follow the instructions that the textbook gives. It seems like I have to have a Entry.cpp file. Thanks for your suggestion. If I don't use an Entry.cpp file I will lose points.

[seeplus]

As three files (including main.cpp for testing):

entry.h

#pragma once

template <class KeyType, class ValueType>
class Entry {
private:
	KeyType key {};
	ValueType value {};

protected:
	void setKey(const KeyType& searchKey);

public:
	Entry();
	Entry(const KeyType& searchKey, const ValueType& newValue);
	ValueType getValue() const;
	KeyType getKey() const;
	void setValue(const ValueType& newValue);

	bool operator ==(const Entry<KeyType, ValueType>& rightHandValue) const;
	bool operator >(const Entry<KeyType, ValueType>& leftHandValue) const;
};

template <class KeyType, class ValueType>
class Entry1 : public Entry<KeyType, ValueType> {
public:
	Entry1() : Entry() {}
	Entry1(const KeyType& searchKey, const ValueType& newValue) : Entry<KeyType, ValueType>(searchKey, newValue) {}
	void setKey(const KeyType& searchKey) { Entry<KeyType, ValueType> ::setKey(searchKey); }
};

#include "entry.cpp" 

entry.cpp

template <class KeyType, class ValueType>
inline Entry<KeyType, ValueType>::Entry() {}

template <class KeyType, class ValueType>
inline Entry<KeyType, ValueType>::Entry(const KeyType& searchKey, const ValueType& newValue) : key(searchKey), value(newValue) {}

template <class KeyType, class ValueType>
inline ValueType Entry<KeyType, ValueType>::getValue() const { return value; }

template <class KeyType, class ValueType>
inline KeyType Entry<KeyType, ValueType>::getKey() const { return key; }

template <class KeyType, class ValueType>
inline void Entry<KeyType, ValueType>::setValue(const ValueType& newValue) {
	value = newValue;
}

template <class KeyType, class ValueType>
inline void Entry<KeyType, ValueType>::setKey(const KeyType& newKey) {
	key = newKey;
}

template <class KeyType, class ValueType>
inline bool Entry<KeyType, ValueType>::operator==(const Entry<KeyType, ValueType>& rightHandValue) const {
	return rightHandValue.key == key;	// Might want to also compare values as well
}

template <class KeyType, class ValueType>
inline bool Entry<KeyType, ValueType>::operator>(const Entry<KeyType, ValueType>& rightHandValue) const {
	return rightHandValue.key > key;	// Might want to also compare values as well
}

main.cpp

#include <iostream>
#include <iomanip>
#include "entry.h"

int main()
{
	Entry e(1, 2);
	Entry1 e1(5, 6);

	std::cout << e.getKey() << "  " << e.getValue() << '\n';
	std::cout << e1.getKey() << "  " << e1.getValue() << '\n';

	e1.setValue(4);
	e1.setKey(3);

	std::cout << e1.getKey() << "  " << e1.getValue() << '\n';

	Entry e2(1, 5);

	std::cout << std::boolalpha << (e2 == e) << '\n';
	std::cout << std::boolalpha << (e2 > e) << '\n';
}

[Lacy9265]

I have figured out the bool operators.
I'm having trouble with these functions:
protected:
void setKey(const KeyType& searchKey);

public:
Entry();
Entry(const KeyType& searchKey, const ValueType& newValue);
ValueType getValue() const;
KeyType getKey() const;
void setValue(const ValueType& newValue);

[Lacy9265]

I right now I'm getting issues where I get errors saying function already defined. I'm using the same entry.h file I have posted before.

 
template <class KeyType, class ValueType>
inline Entry<KeyType, ValueType>::Entry() {}

template <class KeyType, class ValueType>
inline Entry<KeyType, ValueType>::Entry(const KeyType& searchKey, const ValueType& newValue) : key(searchKey), value(newValue) {}

template <class KeyType, class ValueType>
inline ValueType Entry<KeyType, ValueType>::getValue() const { return value; }

template <class KeyType, class ValueType>
inline KeyType Entry<KeyType, ValueType>::getKey() const { return key; }

template <class KeyType, class ValueType>
inline void Entry<KeyType, ValueType>::setValue(const ValueType& newValue) {
	value = newValue;
}

template <class KeyType, class ValueType>
inline void Entry<KeyType, ValueType>::setKey(const KeyType& newKey) {
	key = newKey;
}


template < class KeyType, class ValueType>
bool Entry<KeyType, ValueType>::operator==(const Entry<KeyType, ValueType>&rightHandItem) const
{
return (key == rightHandItem.getKey());
}  


template < class KeyType, class ValueType>
bool Entry<KeyType, ValueType>::operator>(const Entry<KeyType, ValueType>& leftHandItem) const
{
	return (key > leftHandItem.getKey());
}

[AbstractionAnon]

As Handy Andy already pointed out using including a .cpp is going to cause problems.
You're getting duplicate errors because entry.cpp is being compiled twice.
Once as a result of the include.
And again when your IDE sees the .cpp file and compiles entry.cpp a second time.
Since you can't change the name, your best best is to go into your IDE's property page for entry.cpp and mark it as non-compileable. This way your IDE will not try to compile it because it is a .cpp file. Your include will not be affected.

In Visual Studio, right click on entry.cpp; Select properties. The property page is displayed. Under General, Exclude from Build; select YES and save the property page. Other IDE's may vary.

[seeplus]

Or see my code above and mark the function definitions as inline.

Or to not compile entry.cpp, right click it and select Remove and then Remove (NOT DELETE).

[Lacy9265]

If I would follow what AbstractionAnon said. When I zip the project and open the project on another machine the build for entry.cpp would be the same as it was on my computer.

[AbstractionAnon]

When I zip the project and open the project on another machine the build for entry.cpp would be the same as it was on my computer.

That's correct.