• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0

C++ vector/matrix size question

3 posts in this topic

hello everyone, i have a question about the c++ language, so i will start by a example:

[CODE]void do_something(int v[]);[/CODE]

why i don't need to specify the vector size in the function parameter?
how does the compiler knows the size of it? (i think that it takes from the function call... right?)

another example:

[CODE]void do_something2(int v[][5]);[/CODE]

ok ok, i don't have to specify the lines size, but i have to specify the columns size... if the compiler can "take automatically" the lines size (as in the first example), why it don't take the columns too?

(sorry for the bad english, it's not my native language)
thank you. Edited by lucaswrk

Share this post

Link to post
Share on other sites
The function, do_something, doesn't know the size of your array. The first is basically equivalent to this ([i]which works because arrays can decay to pointers[/i]):[code]void do_something(int* v);[/code]
With the second case, you can only omit one of the dimension-sizes, because to address/look-up the array, the compiler needs to know at least one of the dimension sizes. In other words, the array-look-up logic doesn't need to know the size of one dimension -- a 3d array only needs 2 sizes known, a 4d array only needs 3 sizes known.

e.g. the logic for looking up a value in a 3d array might look like:
[code]int Lookup( int* array, int x, int y, int z, int sizeX, int sizeY, int sizeZ )
int* value = array + x + y*sizeX + z*sizeY;
return *value;
}[/code] Edited by Hodgman

Share this post

Link to post
Share on other sites
so, in an abstract way, it works like this (?):

int array[[color=#a52a2a]5[/color]][[color=#006400]5[/color]];

[color=#006400] 0x0002[/color]
[color=#006400] 0x0003[/color]
[color=#006400] 0x0004[/color]
[color=#006400] 0x0005[/color]
[color=#006400] 0x0006[/color]
[color=#006400] 0x0008[/color]
[color=#006400] 0x0009[/color]
[color=#006400] 0x000A[/color]
[color=#006400] 0x000B[/color]
[color=#006400] 0x000C[/color]

int* value = array+1..5 //for looking up a column value from line 1
int* value = array+6+1..5 //for looking up a column value from line 2
//and so on.


thank you.

Share this post

Link to post
Share on other sites
Qrrays are indexed from zero, and [5] means 5 elements total, i.e. 0 .. 4.

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  
Followers 0