Thread: Extractor overloading and memberwise assignment for Cartesian class

I am making a program with a Cartesian class. I want the user to be able to input 2 coordinates, but when I run it it doesn't ask for any values to be entered. It gives this output
Please enter the first coordinates: Please enter the second coordinates: (4.86129e-270, -1.97785e-41)
(4.86143e-270, -1.97785e-41)

Here is the code

Code:

#include <iostream>
#include <istream>
#include <ostream>


using namespace std;


class Cartesian
{
private:
double x;
double y;
public:
Cartesian( double= 0, double= 0);
friend istream& operator>>(istream&, Cartesian&);
friend ostream& operator<<(ostream&, const Cartesian&);


};


Cartesian::Cartesian(double a, double b)
{
    x=a;
    y=b;
}


istream& operator>>( istream& in, Cartesian& num)
{
    double a, b;
    num.x= a;
    num.y= b;


    in >> a >> b;


return in;
}


ostream& operator<<( ostream& out, const Cartesian& num)
{
    cout << "(" << num.x << ", " << num.y << ")" << endl;


return out;
}


int main()
{
    Cartesian coord1, coord2;
    cout << "Please enter the first coordinates: ";
    cin >> coord1;
    cout << "Please enter the second coordinates: ";
    cin>> coord2;
    cout << coord1;
    cout << coord2;
    
    
    return 0;
}

Also, I want to add a memberwise assignment function to assign the values of coord1 to coord2. How would I go about doing so?

And what should I do as an alternative?

Assign the values of a and b to num after reading a and b from the stream
Kurt

Okay so I've changed my code around a bit, but now I get errors saying the x and y in x=c and y=d don't name types. What should I do?

Code:

#include <iostream>#include <istream>
#include <ostream>


using namespace std;


class Cartesian
{
private:
double x;
double y;
public:
Cartesian( double= 0, double= 0);
friend istream& operator>>(istream&, Cartesian&);
friend ostream& operator<<(ostream&, const Cartesian&);
double c;
double d;
x=c;
y=d;


};


Cartesian::Cartesian(double a, double b)
{
    x=a;
    y=b;
}


istream& operator>>( istream& in, Cartesian& num)
{
	in >> num.x;
	in >> num.y;
    


return in;
}


ostream& operator<<( ostream& out, const Cartesian& num)
{
	cout << "(" << num.x << ", " << num.y << ")" << endl;


return out;
}


int main()
{
	Cartesian coord1, coord2;
    cout << "Please enter the first x-coordinate: ";
	cin >> coord1.c;
	cout << "Please enter the first y-coordinate: ";
	cin >> coord1.d;
	 cout << "Please enter the second x-coordinate: ";
	cin >> coord2.c;
	cout << "Please enter the second y-coordinate: ";
	cin >> coord2.d;
	


	cout << coord1;
	cout << coord2;


	
	
	return 0;
}

I've gotten the program to run, but it doesn't ask the user to input data. Can anyone tell me what part of my code is wrong?

Code:

#include <iostream>
#include <istream>
#include <ostream>


using namespace std;


class Cartesian
{
private:
double x;
double y;
public:
Cartesian( double= 0, double= 0);
friend istream& operator>>(istream&, Cartesian&);
friend ostream& operator<<(ostream&, const Cartesian&);
}
;


Cartesian::Cartesian(double a, double b)
{
    x=a;
    y=b;
}


istream& operator>>( istream& in, Cartesian& num)
{
    in >> num.x;
	in >> num.y;
    


return in;
}


ostream& operator<<( ostream& out, const Cartesian& num)
{
	cout << "(" << num.x << ", " << num.y << ")" << endl;


return out;
}


int main()
{
	Cartesian coord1, coord2;
	cout << "Please enter the first coordinates in the form x y: ";
	cin >> coord1;
	cout << "Please enter the second coordinates in the form x y: ";
	cin >> coord2;
	cout << coord1;
	cout << coord2;


	
	
	return 0;
}

I can't reproduce your problem. When I run the program, I can enter, for example:

Code:

Please enter the first coordinates in the form x y: 1.2 3.4
Please enter the second coordinates in the form x y: 5.6 7.8
(1.2, 3.4)
(5.6, 7.8)

Process returned 0 (0x0)   execution time : 22.090 s
Press any key to continue.

So it works for me. If you have any information besides "it doesn't ask the user" it would help.