Room for lazyPower and George Edison

lazyPower

02:32

Allo there

George Edison

Hello.

lazyPower

When working with the enum type in C++, is the point just so your string literals give meaningful names? because it doesnt operate like an array, meaning i cant do function method takes the int index of an enum and hten print the string

George Edison

Right.

Well... enums provide type safety.

lazyPower

eg: enum BirthStones { Garnet = 1, Amethys, Aquamarine.... }

George Edison

Unlike the old C style #define's, enum's are type safe.

lazyPower

02:33

then i have a method later on in the class, getBirthStones(int month) { // stuff goes here return BirthStone(month); }

George Edison

(You can't pass an enum where an string is expected.)

Right.

int to enum is an invalid conversion.

lazyPower

so in order to have this work properly, i need to create an indexed array, that coinsides with the ENUM, and then print that?

George Edison

...assuming that's what you're doing.

lazyPower

the criteria: Create an enumeration for the months in the year, add a function named getBirthstone that returns the birthstone based on the month.

George Edison

Well... why can't getBirthStone() have the enum as its parameter?

lazyPower

02:35

i was trying do it in reverse, using an enum of the birthstones

so, if i pass in the enum as a parameter, i can call it by index?

let me gist my open buffers

George Edison

You can convert an enum to an int if you need to.

lazyPower

gist: 969870, 2011-05-13 02:36:43Z

George Edison

I'll point out a few things as I come across them...

lazyPower

ok

George Edison

- First off, displayMenu() should probably return the value it gets from cin instead of putting it in a global variable.

Oh, I see what you're doing.

You're having the user input an integer, and you wan't it stored using the enum.

Well there's two things you can do...

- First, you could have a function in Person that has a switch that converts the int into the appropriate enum.

lazyPower

02:41

ok going to whip that up then

George Edison

- Or you could simply use int's throughout and only use the enum for comparison.

(Which might be a better option.)

lazyPower

hmmm

i dont follow

George Edison

What I mean is... continue to use int for storing the month...

lazyPower

right

George Edison

...and then whenever you're comparing another value to the int, use the enum like so:

> if(month == GARNET)...

...or whatever. In that case, the only purpose of the enum is to keep you from hardcoding integer values for the items.

(Since that's exactly what we're trying to avoid.)

lazyPower

02:45

ok hang on let me try this and see if i'm following. right now i'm trying to figure out what i've done wrong in my switch in birthdayInfo

its stopped compiling with an issues about crosses initialization of std::string inputName

George Edison

Can I see what you have?

lazyPower

*i changed the variable name from name, to inputName on line 41

Done: gist.github.com/969877

George Edison

Hmm... another problem...

lazyPower

also this isnt going to work the way i have it, with displayMenu() as the criteria

it will run twice

i just noticed that

George Edison

Right.

I was about to say that.

You need to store the value somewhere.

... or use a do...while() loop.

...which is probably a better idea.

That way the menu will always be display once.

So you have:

> do {

lazyPower

02:48

DO { // stuff } while (DisplayMenu() != -1)

George Edison

Right, except you should store the value you get from displayMenu().

Can I stick this in a pastebin?

lazyPower

hmmm

sure

or you can fork it on gist :P

i use gist because i have a hook in vim to auto-post to it.

George Edison

pastebin.com/xYEwSv7J

lazyPower

object heirarchy, does case1 cause myperson to fall out of scope?

George Edison

No.

First of all, a case isn't a new scope.

lazyPower

02:56

tmp/cccttnc9.o: In function `main':
birthdayInfo.cpp:(.text+0x1dc): undefined reference to `Person::setName(std::basic_string<char, std::char_traits<char>, std::allocator<char> >)'

George Edison

(This really surprises a lot of people.)

lazyPower

i didnt think so but C++ says its angry about it

George Edison

Can I see what you have now?

lazyPower

sure

gist.github.com/969891

George Edison

Are you linking person.cpp?

That's the only thing I can think of that would cause that problem.

lazyPower

02:59

ugh right

the linux toolchains demand i do that

just including the prototype header wont do that automagically

George Edison

Otherwise you have a reference to a function that doesn't exist in code :)

lazyPower

thats what i get for putting off this homework/project for two weeks, i forgot everything :|

George Edison

When you compile main.cpp, you'll end up with main.o which contains the code for main.cpp.

lazyPower

I took this as an opportunity to learn the linux C/C++ toolchain vs using VS that school teaches

George Edison

That code references Person::setName which is declared in person.h.

lazyPower

03:00

If i were to drop Vim, what IDE would you recommend for C++ development?

George Edison

Qt Creator!

lazyPower

you said something about the QT ide not to long ago i beleive

ok let me apt-get it

George Edison

Yup, it's the best - even for straight C++ (without using Qt at all).

lazyPower

wow

307 megs of libs

\o/

George Edison

It's big.

lazyPower

03:01

i see

wonder how its going to perform on my netbook

George Edison

Its performance is good.

I think all those files are related to the Qt dev. headers / libs.

No clue why Qt Creator needs those, though.

lazyPower

shrug i leave all that up to the maintainers. I gave up on pondering package dependencies a long time ago

if they say so, by all means i'll eat the space to house them

i hate building packages and then trying to fix it when i try to circumvent repositories dependencies. Slack taught me quite a bit about that.

George Edison

I've learned to leave them alone too... ever since I force-installed a package on an Ubuntu install - and it corrupted the package DB so bad that I had to reinstall pretty much every package on the system.

lazyPower

oh dude this is sexy

grokks qtcreator

George Edison

Let me know if you have any questions about using it.

The code-completion and indexing in Qt Creator is unparalleled.

lazyPower

03:11

so if i dont use a project, it wont let me build/debug?

George Edison

Yeah.

...but that's common with most IDEs (at least on Linux).

lazyPower

bummer

George Edison

Creating a project is pretty easy though.

lazyPower

going through the wizard now

George Edison

For a straight C++ app, just choose "Qt Console" and delete everything it creates for you.

lazyPower

03:15

ah i chose C++ Shared Library anbd just removed the QT dependencies

George Edison

@lazyPower Oh... that will create a .so binary.

lazyPower

i see

Dude i cant get over this interface

this is slick as hell

George Edison

It's not bad.

A bit of searching has discovered that in order to remove Qt dependencies, you need to add this to your .pro file:

> CONFIG -= qt

...and that will create a generic run-of-the-mill C++ executable.

If you ever are interested in learning Qt, let me know.

lazyPower

Let me get the basics of C++ down and i'll consider it :)

right now i'm happy being a VB/C#/PHP developer, and C++ for school. I thought about picking up Python, but C++ may be the route i go instead for the short-term since I'll have a few months of schooling in it.

string Person::getBirthStone(int month)
{
switch (month)
case Garnet:
return "Garnet";
case Amethyst:
return "Amethyst";
case Aquamarine:
return "Aquamarine";
case Diamond:
return "Diamond";
}

was that along the lines of what you were getting at?

George Edison

03:31

That would work.

lazyPower

shit the criteria was enum of months but thats a quick fix

@GeorgeEdison defining that enum, i should be able to pass it in as a parameter of the prototyped class method correct? string Person::getBirthStone(Months month) correct?

George Edison

@lazyPower That function just returns a string for the month right?

lazyPower

negative, it returns a string of the birthstone

hang on i'll pastebin the files

pastebin.com/vPVKJfWM

George Edison

Ah, I see.

Yup, that will work fine.

lazyPower

:|

says on line 40 of person.cp: /home/charles/Dropbox/School/CeePlusPlus/BirthdayProfile-build-desktop/../BirthdayProfile/person.cpp:40: error: ‘std::string Person::getBirthStone’ is not a static member of ‘class Person’

/home/charles/Dropbox/School/CeePlusPlus/BirthdayProfile-build-desktop/../BirthdayProfile/person.cpp:40: error: ‘Months’ was not declared in this scope

does not compute as to why its not valid in my brain

its declared as public in the class, and htis is the class body

so what scope is there that its not defined in?

George Edison

03:45

Is it declared in Person.h?

lazyPower

yep

George Edison

Can I see Person.h?

lazyPower

in the public block

its on that last paste

George Edison

Ah, I see it.

lazyPower

line 83 and below

George Edison

03:47

For the months error, you need to change Months in the function to Person::Months, IIRC.

Since you've declared it inside the class, you need to use the class qualifier to access it.

lazyPower

/home/charles/Dropbox/School/CeePlusPlus/BirthdayProfile-build-desktop/../BirthdayProfile/person.cpp:40: error: ‘std::string Person::getBirthStone’ is not a static member of ‘class Person’

/home/charles/Dropbox/School/CeePlusPlus/BirthdayProfile-build-desktop/../BirthdayProfile/person.cpp:40: error: ‘Months’ is not a member of ‘Person’

>.>

makes me want to punch babies

George Edison

Hang on. Lemme fire up Qt here...

Small note... Person:48 - you spelled February wrong :)

lazyPower

ok

doh

George Edison

It compiles for me...

lazyPower

oh what the heck

George Edison

03:50

...what's in main.cpp?

lazyPower

pastebin.com/tUFPmTpU

George Edison

Yup. It all builds cleanly for me? What errors are you still getting?

lazyPower

/home/charles/Dropbox/School/CeePlusPlus/BirthdayProfile-build-desktop/../BirthdayProfile/person.cpp:40: error: ‘std::string Person::getBirthStone’ is not a static member of ‘class Person’

/home/charles/Dropbox/School/CeePlusPlus/BirthdayProfile-build-desktop/../BirthdayProfile/person.cpp:40: error: ‘Months’ is not a member of ‘Person’

/home/charles/Dropbox/School/CeePlusPlus/BirthdayProfile-build-desktop/../BirthdayProfile/person.cpp:41: error: expected ‘,’ or ‘;’ before ‘{’ token

George Edison

Are all of the files added to the project?

lazyPower

yep

George Edison

03:53

Just to make sure everything is synced, can you put all of the files somewhere again?

Just to make sure I have exactly what you have.

lazyPower

db.tt/IOssGHx

George Edison

Aha! I reproduced them.

lazyPower

what i did?

haha

George Edison

You've got two different functions for getBirthStone().

One takes an int - the other takes a Month.

They both need to be the same or the compiler thinks you're trying to declare a new function...

...which is not possible. Hence the error.

...and what happened to the Months enum?

I can't find it anymore.

lazyPower

err

its in there

this is odd

it made two directories

one of the project folder, the initial directory, now its gone one with a -build-desktop appended.

George Edison

04:00

Actually...

Qt creates a second directory with the compiled files in it and sticks -build-desktop on the end to distinguish it.

lazyPower

wth

it IS missing

throws a fit

i must have been editing while debugging and it vaped my changes

Yeah and that method declaration in the prototype did have months as its param

visible in the pastebin

i made changes while the IDE was doing something and it didnt take any of my changes

how do i stop the IDE from sitting in limbo durin ga failed build so i dont have this issue again?

George Edison

"sitting in limbo durin ga failed" - what do you mean?

lazyPower

it was sitting in limbo during the failed build. i saw the debug screen, and it did nothing. i made changes and apparently after cleaning the build it erased my source changes.

George Edison

The debug screen? You mean the button under "Design" on the left?

lazyPower

imgur.com/Vy63h

the view in the center

George Edison

04:11

Oh, right.

That's the debug view (as opposed to the edit view). Weird though - I can always edit files when it's debugging.

Does it compile now?

lazyPower

and it doesnt wipe changes?

yeah, trying to interface with it in the output screen. i've either got a logic error or its not reading my input.

rather, the application output screen

George Edison

@lazyPower Oh, you mean the output window at the bottom?

Yeah, it's not interactive.

lazyPower

Yessir, tab 3

that makes sense :)

haha

George Edison

You'll have to run it in a terminal.

lazyPower

ok

lazyPower

04:32

Awesome

i think the growing pains are over

i understand what i was trying to do now that i've failed at it horibly four or five times and now i have a working, and compiling project thats doing what i tell it to

hi5 @GeorgeEdison, i owe you man.

Transcript for

Room for lazyPower and George Edison