simple class

[pimster987]

Im having problems making a simple class. I made classes before but with the class I am working on now I cant seem to figure out the problem. When I compile it it gives me an error saying "23 C:\Dev-Cpp\project.cpp prototype for `int book::center(int, int)' does not match any in class `book' "

#include <cstdlib>
#include <iostream>

using namespace std;

class book {
int length, width, heigth, date;
public:
book (int, int, int, int);
int surfaceArea ();
int volume ();
int year ();
int center ();
};

book::book(int a, int b, int c, int d){
width=a;
length=b;
heigth=c;
date=d;
}

int book::center(int a, int b){
length=b/2;
width=a/2;
return length,width;
}

int book::volume(int a, int b, int c){
length=b;
width=a;
heigth=c;
return length*width*heigth;
}

int book::year(int d){
year=d;
return 2009-date;
}




int main(int argc, char *argv[])
{


cout <<"This book is "<<book.year(1980)<<" years old."<<endl;
system("PAUSE");
return EXIT_SUCCESS;
}

[helios]

The error is pretty clear. You only have three methods in book: surface(), volume(), and year(). No center().

[pimster987]

sorry I figured that out that I was missing center () but when I put that in it still gives me the same error.

[helios]

The declared center() takes no parameters. The defined center takes two ints.

[pimster987]

Oh alright I see now. But I thought if you put center() its the same as center(int, int). Now I just have one more problem which is in the cout out part. its says 48 C:\Dev-Cpp\project.cpp expected primary-expression before '.' token

#include <cstdlib>
#include <iostream>

using namespace std;

class book {
int length, width, heigth, date;
public:
book (int, int, int, int);
int surfaceArea ();
int volume (int, int, int);
int year (int);
int center (int, int);
};

book::book(int a, int b, int c, int d){
width=a;
length=b;
heigth=c;
date=d;
}

int book::center(int a, int b){
length=b/2;
width=a/2;
return length,width;
}

int book::volume(int a, int b, int c){
length=b;
width=a;
heigth=c;
return length*width*heigth;
}

int book::year(int d){
date=d;
return 2009-date;
}




int main(int argc, char *argv[])
{


cout <<"This book is "<<book.year(1980)<<" years old."<<endl;
system("PAUSE");
return EXIT_SUCCESS;
}

[helios]

cout <<"This book is "<<book.year(1980)<<" years old."<<endl;
book is not declared. Rather, it's declared as a type, but you need an object, there.

[pimster987]

OK so now I wrote it like this and it works finally. I need to use a destructor in class but our teacher never really explained it. So I tried to insert ~book() under book (int,int,int,int) as my destructor but it says [Linker error] undefined reference to `book::~book()' .

#include <cstdlib>
#include <iostream>

using namespace std;

class book {
int length, width, heigth, date;
public:
book ();
book (int, int, int, int);

int surfaceArea ();
int volume (int, int, int);
int year (int);
int center (int, int);
};

book::book(int a, int b, int c, int d){
width=a;
length=b;
heigth=c;
date=d;
}

int book::center(int a, int b){
length=b/2;
width=a/2;
return length,width;
}

int book::volume(int a, int b, int c){
length=b;
width=a;
heigth=c;
return length*width*heigth;
}

int book::year(int d){
date=d;
return 2009-date;
}




int main(int argc, char *argv[])
{

book car (5,5,5,1980);

cout <<"This book is "<<car.year(1980) <<" years old"<<endl;
system("PAUSE");
return EXIT_SUCCESS;
}

[helios]

book car (5,5,5,1980);
Oh, God, my brain!

I need to use a destructor in class but our teacher never really explained it.

Only for classes that contain pointers. This isn't the case.

[pimster987]

lol well this is my first time ever taking a computer programming class. The teacher I have now doesnt teach very well. All he does is put codes on the board and expect us to know what it means.