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Seperate file, type conversion

toomanystars (151)
Hello everyone,

I have two file, interface, and implementation.

Here's the interface

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#ifndef CARTESIAN_H
#define DTIME_H

using namespace std;

class Cartesian{
public:
	Cartesian();
	Cartesian(int a, int b);
	friend istream& operator>>(istream& in,Cartesian& c);
	friend ostream& operator<<(ostream& out,Cartesian& c);
	int input(char* c);
	Cartesian operator+(Cartesian& c);
	Cartesian operator-(Cartesian& c);
	bool operator==(Cartesian& c);
	operator Polar();
		
	

private:
	int x, y;

};

#endif


Here's the implementation

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#include "stdafx.h"
#include <conio.h>
#include <iostream>
#include <iomanip>
#include "cartesian.h"
#include "polar.h"

using namespace std;
const int MAX=20;

Cartesian::Cartesian(){}
Cartesian::Cartesian(int a, int b):x(a),y(b){}
int Cartesian::input(char* c){
	for(int i=0;i<strlen(c);i++){
		if(!isdigit(*(c+i))){
			cout<<"Invalid input!";
			exit(1);
		}

	}
	return atoi(c);
}
istream& operator>>(istream& in,Cartesian& c){
	char next[MAX];
	cout<<"Enter the 'x' co-ordinate: ";
	in>>next;
	c.x=c.input(next);
	cout<<"Enter the 'y' co-ordinate: ";
	in>>next;
	c.y=c.input(next);

	return in;
}
ostream& operator<<(ostream& out,Cartesian& c){
	out<<"("<<c.x<<","<<c.y<<")"<<" = "<<"(x,y)";
	return out;
}	
Cartesian Cartesian::operator+(Cartesian& c){
	Cartesian temp;
	temp.x=x+c.x;
	temp.y=y+c.y;
	return temp;
}
Cartesian Cartesian::operator-(Cartesian& c){
	Cartesian temp;
	temp.x=x-c.x;
	temp.y=y-c.y;
	return temp;
}
bool Cartesian::operator==(Cartesian& c){
	if(c.x==x && c.y==y)
		return true;
	else
		return false;
}
Cartesian::operator Polar(){//problem here, compiler gives errors, don't know 
                            //how the function definition should look

	//code here
}


The problem is that I have the prototype in the interface file called "operator Polar()" but I don't know how the syntax looks int he implementation file. I have tried all the difference combinations (I think) but met with little success.

Could someone please show me the proper syntax for the application file so that the conversion function "operaor Polar()" will be recognized? This way, I don't have to put the code into the interface.

Thanks,

Mike
closed account (zb0S216C)
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Cartesian::operator Polar()
{
    return(Polar(/*...*/));
}

As simple as that.

Wazzak
Last edited on
toomanystars (151)
That's what I did, but Visual Studio is underling it in red.

Mike
closed account (zb0S216C)
What does the error say?

Wazzak
toomanystars (151)
"Error:class"Cartesian" has no member "operator Polar"
closed account (zb0S216C)
The Cartesian class needs to know about Polar. Since you'll be invoking a constructor of Polar during the return of Cartesian::operator Polar(), you'll have to fully define Polar before Cartesian. For instance:

Polar.h

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#if !defined POLAR_IMPL
#define POLAR_IMPL

struct Polar
{
    // ...
};

#endif

Cartesian.h

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#if !defined CARTESIAN_IMPL
#define CARTESIAN_IMPL

#include "Polar.h"

struct Cartesian
{
    operator Polar(); // OK; "Cartesian" now knows about "Polar".
};

endif

On a side-note, I strongly recommend that you remove using namespace std from any headers, because it can cause name conflicts.

Wazzak
toomanystars (151)
I will take your advice!

Thanks a lot,

Mike
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