Help With Structures and Classes (C++)

[ghall]

So I am continuing my C++ studies. A while ago, I wrote a Madlibs program as an assignment for my C++ tutors, and my new assignment is to modify the code to use structures and/or classes, and I'm stumped. Can somebody give me a few ideas. The code is about 150 lines long, so I've uploaded it as an attachment.

Feel free to compile and play around with it too if you so desire.

[toddburch]

What are you stumped on? I see no attempt at a structure or class definition.

Todd

[ghall]

What are you stumped on? I see no attempt at a structure or class definition.

Todd

I have no idea where to begin. I know what I want to do, but I don't know how I should go about it.

[toddburch]

Also, it's looking pretty much (exclusively) like C code, not C++ code.

Todd

[toddburch]

Well, decide if you want C code with Structures, or C++ code with Structures and/or Classes first.

Can you verbalize what you want to do?

Todd
(I know what to do - but you need to show you know.)

[ghall]

Well, decide if you want C code with Structures, or C++ code with Structures and/or Classes first.

Can you verbalize what you want to do?

Todd
(I know what to do - but you need to show you know.)

I guess I need to use structures. I'm trying to create a structure for blank spaces and an structure for parts of speech. I'm confused at the order I should do them, and how to implement them in the main code.

I'm not even really sure what I'm doing. I'm having a tough time grasping classes and structures.

[toddburch]

OK, so a structure of group of related data, made up of individual data types and/or other structures (basically). Think of a structure as a programmer defined data type.

What variables do you have now that you want to group together into a structure?
Todd

[ghall]

OK, so a structure of group of related data, made up of individual data types and/or other structures (basically). Think of a structure as a programmer defined data type.

What variables do you have now that you want to group together into a structure?
Todd

Right now, I just want the part of speech to be a variable (noun, verb, etc.).

[toddburch]

OK. Grab your C book and let's see your first attempt at defining a structure.

Todd

[ghall]

OK. Grab your C book and let's see your first attempt at defining a structure.

Todd

I don't really have a book, I'm just being taught off a white board. Anyway here's my first program using structures. I got some help with it, but I can't seem to grasp the concept of structures. It's so frustrating, I was doing so well until I reached this point in my lessons. :(

#include <stdio.h>

//this structure represents walls in a room
struct wall{
int height;
int length;
};
//this structure represents a room
struct room{
wall north,south,east,west,updn;
};

//this function calculates the area of a wall
int area (wall mw){
return mw.height*mw.length;
}

//this function calculates the area of the floor and ceiling
int updown (room mc){
return mc.north.length*mc.east.length;
}

//this function calculates the total area of a room
int roomarea (room mr){
return area(mr.north)+area(mr.south)+area(mr.east)+area(mr.west)+updown(mr)+updown(mr);
}

//this function calculates the area of the walls and the ceiling of a room
int paintarea (room ma){
return area(ma.north)+area(ma.south)+area(ma.east)+area(ma.west)+updown(ma);
}

//this function calculates the total area of the floor
int carpetarea (room mp){
return updown(mp);
}


int main()
{
room r;

//take in the room height and assign it to the nort south west and east walls
printf ("Height\n");
scanf ("%d", &r.north.height);
r.south.height = r.north.height;
r.west.height = r.north.height;
r.east.height = r.north.height;


//take in the room length and assign it to the north and south walls
printf ("Length\n");
scanf ("%d", &r.north.length);
r.south.length = r.north.length;

//take in the room width and assign it to the east and west walls
printf ("Width\n");
scanf ("%d", &r.west.length);
r.east.length = r.west.length;

//assign the functions roomarea paintarea and carpetarea to integers
int myarea = roomarea (r);
int mypaintarea = paintarea (r);
int mycarpetarea = carpetarea (r);

//output the results
printf ("%d foot area\n%d paint area\n%d carpet area\n", myarea, mypaintarea, mycarpetarea);
}

[ChrisBrightwell]

Right now, I just want the part of speech to be a variable (noun, verb, etc.).

If you want to use a class or struct, then, it would look something like this:

struct BlankSpace
{
private:
String type; // adj., noun, adv., etc.
String value; // value given by user.

public:
BlankSpace(); // default constructor
BlankSpace(const BlankSpace&) // copy constructor
~BlankSpace(); // default destructor
BlankSpace& operator= (const BlankSpace& bs);

void setType(String s);
void setValue(String s);
String getType();
String getValue();
}

[toddburch]

Chris, I wasn't aware you could define constructors and destructors with structures.

BTW, he's sticking with C, so that C++ example doesn't help him. (him?)

Todd

[iSee]

Chris, I wasn't aware you could define constructors and destructors with structures.

BTW, he's sticking with C, so that C++ example doesn't help him. (him?)

Todd

Under C++, structs and classes are the same thing, the only difference being that members are public by default for structs, and private by default for classes.

(But as a style thing, I'd recommend only using structs in the traditional way.)

[ChrisBrightwell]

Chris, I wasn't aware you could define constructors and destructors with structures. Structs and Classes in C++ are basically the same. They differ in the default access of their members (structs default to public, classes to private).

BTW, he's sticking with C, so that C++ example doesn't help him. (him?)I'm not a C guru, by any means, but I don't see why it wouldn't work. Swap String for a char array, maybe, but that's probably the only diff.