Help with School Program (C++)

[jackieAZ]

Hi guys, I'm a beginning programmer in school, and this error is making me terror my hair out. We're learning of classes and such in c++ and I'm assigned to making a rectangle.

I have a member function called setlength() which is supposed to set length to the double len, which the client code inputs, however it keeps telling me that it is invalid use of member function. Any help?

 

 

// function declaration (in its own h file with rectangle class etc declared properly as far as I know)

#ifndef RECTANGLE_H
#define RECTANGLE_H

#include <iostream>
#include <iomanip>

using namespace std;

class rectangle
{
public:
    void setlength(double len);
    void setwidth(double wid);
    double perimeter();
    double area();
    void show();
    double length();
    double width();


private:


};
#endif

// function definition

#include "rectangle.h"

void rectangle::setlength(double len)
{
   length = len;
}

void rectangle :: setwidth(double wid)
{
width = wid;
}
double rectangle :: perimeter()
{
perimeter = length + length + width + width;
return perimeter;
}
double rectangle :: area()
{
area = legnth * width;
return area;
}
void show()
{
return length;
return width;
}

Thanks in advance

[fizzlesticks]

Can't tell from just what you posted. Please use code tags to post you entire class definition and copy/paste the exact error message.

[jackieAZ]

1 minute ago, fizzlesticks said:

Can't tell from just what you posted. Please use code tags to post you entire class definition and copy/paste the exact error message.

done

[fizzlesticks]

Just now, WubGuy said:

done

You declared length() as a member function but you're trying to assign to it as if it were a variable.

[Mira Yurizaki]

I'm not seeing variable declarations. Or am I going insane?

 

EDIT: Okay, since this is OOP land. I'm not seeing any declarations of members. (function names in classes are called methods)

[jackieAZ]

2 minutes ago, fizzlesticks said:

You declared length() as a member function but you're trying to assign to it as if it were a variable.

Thank you! I realize it's a dumb mistake but as I'm discovering programming is not my forte lol

[fizzlesticks]

3 minutes ago, M.Yurizaki said:

(function names in classes are called methods)

In C++ they're called member functions.

edit: Not that it really matters.

[Mira Yurizaki]

2 minutes ago, fizzlesticks said:

In C++ they're called member functions.

I'll just go back to variables and functions then.

 

Either way, I don't see declarations for the variables. Not that it would matter if length is a function and OP wanted to use it as a variable.

[Mira Yurizaki]

Okay, this is the problem I see (I added comments)

#ifndef RECTANGLE_H
#define RECTANGLE_H

#include <iostream>
#include <iomanip>

using namespace std;

class rectangle
{
public:
    void setlength(double len);
    void setwidth(double wid);
    double perimeter();
    double area();
    void show();
    double length(); //This is being declared as a function when it should be a variable
    double width();  //Ditto

private:

};
#endif

Also unless there's a need for other parts of the program to access length and width variables, they should be private. And if they're public, there's also no need to have mutator functions setlength and setwidth.

[jackieAZ]

Thanks both of you, I got it now!

 

 

[Unimportant]

12 hours ago, WubGuy said:

 

#ifndef RECTANGLE_H
#define RECTANGLE_H

#include <iostream>
#include <iomanip>

using namespace std;

//...<snip>

 

 

Do not include namespaces in headers, you'll be polluting the global namespace for any compilation unit that includes your header.

[Ximalas]

On 25.4.2017 at 0:17 PM, Unimportant said:

Do not include namespaces in headers, you'll be polluting the global namespace for any compilation unit that includes your header.

In fact, this header file in its current state doesn't need to include any header files at all.