need help with declaring a 2d int array

need help with declaring a 2d int array

Rash

Member #2,374

May 2002

X-G said:

EDIT: For the record, Rash's post said "... I ever saw in Allegro ..." before he edited it.

You must be imagining things, because I did no such thing.

Ten to one this thread will now degenerate into a C vs C++ vs C99 discussion...Oh wait! ::)

23yrold3yrold

Member #1,134

March 2001

Quote:

All it means that you shouldn't use macros for constants and inline methods. It's as easy as that.

Right. But that's what most people use them for, like it or not. Like, you know, above. Remember this post? Teach the acolyte that macros are evil. When he is a wizard, he can use the black magic when necessary.

William Labbett: MACROS AER TEH EVAL!!1 RUNRUNRUNRUN ...

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spellcaster

Member #1,493

September 2001

Quote:

Teach the acolyte that macros are evil.

That's not needed. Teach everybody that he should use consts and enums for constant values, and inline functions for inline functions.

That's it. No black magic involved here.

EDIT:
Rash: I either want your macro less way for the normal uses of # and ## inside macros, or an apology...
On the other hand, no apology and no macro less way would prove my point as well

--
There are no stupid questions, but there are a lot of inquisitive idiots.

Jonatan Hedborg

Member #4,886

July 2004

Here's a great opportunity to mold a young mind... How would an inlined template-using MIN look? (i have no idea how templates work, but im sure it can be useful )

X-G

Member #856

December 2000

I assume something like:

inline template <typename T> T min(T a, T b) { return (a < b ? a : b); }

EDIT: Forgot return type.

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23yrold3yrold

Member #1,134

March 2001

Off the top of my head ...

   template<class T>
   inline T cadd(T x, T y)
   {
     return (x < y ? x : y);
   }

I might have goofed; it's untested ...

EDIT: All fixed.

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Software Development == Church Development
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Rash

Member #2,374

May 2002

Ok, to stay in character I'll make my 1000th post useful:

#include <algorithm>
std::min(a,b);

[EDIT]
No need to reinvent the wheel, is there?
[/EDIT]

Jonatan Hedborg

Member #4,886

July 2004

X-G: Your code didnt compile.
23: your code worked after i replaced X with z1 and Y with z2

23yrold3yrold

Member #1,134

March 2001

Quote:

No need to reinvent the wheel, is there?

No need to include a standard header for four lines, either. He did ask to see what it would look like ...

Quote:

23: your code worked after i replaced X with z1 and Y with z2

Whoops; right. That's what I get for copying off of Google. ::) All fixed.

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Software Development == Church Development
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X-G

Member #856

December 2000

Quote:

X-G: Your code didnt compile.

How about telling me WHY? Mine is identical to 23's, apart from the placement of "inline" and line breaks/parentheses that shouldn't matter...

23yrold3yrold

Member #1,134

March 2001

I think it's the inline placement, X-G ...

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Software Development == Church Development
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Jonatan Hedborg

Member #4,886

July 2004

I dont know WHY, but im sure this can help

1g++.exe -c main.cpp -o main.o -I"C:/Dev-Cpp/include/c++"  -I"C:/Dev-Cpp/include/c++/mingw32"  -I"C:/Dev-Cpp/include/c++/backward"  -I"C:/Dev-Cpp/include"   
2 
3main.cpp:5: error: syntax error before `<' token
4main.cpp:8: error: definition provided for explicit instantiation
5main.cpp:8: error: non-template used as template
6main.cpp:8: error: syntax error before `{' token
7main.cpp:12: error: ISO C++ forbids declaration of `system' with no type
8main.cpp:12: error: `int std::system' redeclared as different kind of symbol
9C:/Dev-Cpp/include/stdlib.h:362: error: previous declaration of `int 
10   system(const char*)'
11main.cpp:12: error: invalid conversion from `const char*' to `int'
12
13main.cpp:13: error: syntax error before `return'
14 
15C:/Dev-Cpp/include/c++/3.3.1/iostream:77: error: definition provided for 
16   explicit instantiation
17C:/Dev-Cpp/include/c++/3.3.1/iostream:77: error: non-template used as template
18C:/Dev-Cpp/include/c++/3.3.1/iostream:77: confused by earlier errors, bailing out

spellcaster

Member #1,493

September 2001

Rash: I think my point is proven then, eh?

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X-G

Member #856

December 2000

Quote:

main.cpp:5: error: syntax error before `<' token

Err, excuse me? That's where "template" is at. Well, considering how vague errors can be some times, let's just assume it's the placement of the word "inline".

Jonatan Hedborg

Member #4,886

July 2004

yeah, worked when i moved it.. (template <typename T> inline T min(T a, T b) { return (a < b ? a : b); })

Rash

Member #2,374

May 2002

Make the return value a reference and you'll have nailed it.

spellcaster: http://www.parashift.com/c++-faq-lite/big-picture.html#faq-6.14

23yrold3yrold

Member #1,134

March 2001

Quote:

Make the return value a reference and you'll have nailed it.

Return a reference? I can see the parameters as references, but by constructing the object right on the return statement ... well, I didn't know you could beat that. I might be wrong, but what are we returning a reference to?

BTW, that is the coolest new entry into the C++ FAQ Lite ever. 8-)

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Software Development == Church Development
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Rash

Member #2,374

May 2002

Well in that case make the parameters references as well. The declaration of std::min, after all, is:

template <class T> const T& min(const T& a, const T& b);

spellcaster

Member #1,493

September 2001

rash: what's your point?
Please read your own post. Then my reply.
Then think.

You even quoted me saying that there are uses for macros. Then you replied that this "pisses you off".
I guess this means that you either have a better way to handle these situations, or that you either impolite and/or challenged by the concept of independent thought, and thus need to repeat the old dogmas ("Macros are evil, sha-la-la-la").

While I can understand the latter, you've still been rude

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There are no stupid questions, but there are a lot of inquisitive idiots.

Kitty Cat

Member #2,815

October 2002

Wouldn't it be hard to create an inline min() that handles floats, doubles, chars, and ints, without using C++? That's one of the problems I had with my game, I had inline min()/max() functions, but they were messing up because it took ints, but I was passing floats (though I wasn't initially aware of this). I changed them to defines like Allegro has and now it works hunky-dory.

Though I do kinda wish the inline functions worked.. branchless min/max is a good thing to have.

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ReyBrujo

Moderator

January 2001

KC, you could send a third parameter stating the type of the parameters you are sending. As for creating one, this is how DJGPP defines it:

#define min(X, Y) \
    ({ typeof (X) __x = (X), __y = (Y); (__x < __y) ? __x : __y }) 

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Johan Halmén

Member #1,550

September 2001

You know you use too much macros, when you demand syntax hilightning in them.

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