473,396 Members | 1,895 Online
Bytes | Software Development & Data Engineering Community
Post Job

Home Posts Topics Members FAQ

Join Bytes to post your question to a community of 473,396 software developers and data experts.

mat[i][j] = *(*(mat + i) + j) here mat is a pointer to an array of r elements an

6
int mat[r][c];
mat[i][j] = *(*(mat+i) + j) ???

here mat is a pointer to an array of r elements and each elementof mat itself is an array of c elements
then in mat +i ,i gets scaled by c*sizeof(int) thus mat+i is starting address of ith row and then dereferencing it yields first element of ith row but looking at this expression it seems that *(mat + i) is also treated as a address
please help on understanding this way of accessing array elements of multidimensional array
Feb 23 '10 #1
2 1741
weaknessforcats
9,208 Expert Mod 8TB
int mat[r][c];
mat[i][j] = *(*(mat+i) + j) ???
*(*(mat+i) + j) is the pointer syntax for mat[i][j]. That is, take the address of mat and add i * c*sizeof(int) to get the address of mat[i]. Then add j * sizeof(int) to get the adress of the element itself, then de-reference that address to get the actual element.

You might read the article Arrays Revealed in the C Insights Forum.
Feb 23 '10 #2
donbock
2,426 Expert 2GB
That's Arrays Revealed.
Feb 24 '10 #3

Sign in to post your reply or Sign up for a free account.

Similar topics

4
by: Bryan Parkoff | last post by:
I want to allocate pointer array into memory so pointer array contains ten pointers. It would be 4 bytes per pointer to be total 40 bytes. Looks like below for example. unsigned char* A = new...
6
by: Herrcho | last post by:
in K&R Chapter 6.3 it mentions two methods to calculate NKEYS. and points out the first one which is to terminate the list of initializers with a null pointer, then loop along keytab until the...
5
by: Brett | last post by:
Sorry for the rookie question.... If I have a pointer array (for example): char *colors = { "blue", "green" }; and I want to add yellow to this array later in my code....how would I do
3
by: trevorelbourne | last post by:
Hi, I am having trouble accessing the elements of an array using reflection. This is the code I am having trouble with: FieldInfo Fields = Obj.GetType().GetFields(); foreach (FieldInfo fi in...
8
by: ljlevend2 | last post by:
If a property's type is an array and the property is exposed in a PropertyGrid, then the property can be expanded so that the user can view and edit the array elements. But, I've noticed that if...
24
by: RyanTaylor | last post by:
I have a final coming up later this week in my beginning Java class and my prof has decided to give us possible Javascript code we may have to write. Problem is, we didn't really cover JS and what...
6
by: Kumar | last post by:
How should I declare the array elements being half word? and the array elements of the type byte in C?? Please help Kumar
8
by: SP | last post by:
The following code crashes after I add the two nested FOR loops at the end, I am starting to learn about pointers and would like to understand what I'm doing wrong. I think the problem is the way...
5
by: Immortal Nephi | last post by:
I would like to design an object using class. How can this class contain 10 member functions. Put 10 member functions into member function pointer array. One member function uses switch to call...
13
by: pereges | last post by:
Hi, can some one please tell me why this program is not able to function properly. I have a array a and i am trying to create a pointer array b which points to elements less than 40 in a. ...
0
by: ryjfgjl | last post by:
In our work, we often receive Excel tables with data in the same format. If we want to analyze these data, it can be difficult to analyze them because the data is spread across multiple Excel files...
0
by: emmanuelkatto | last post by:
Hi All, I am Emmanuel katto from Uganda. I want to ask what challenges you've faced while migrating a website to cloud. Please let me know. Thanks! Emmanuel
0
BarryA
by: BarryA | last post by:
What are the essential steps and strategies outlined in the Data Structures and Algorithms (DSA) roadmap for aspiring data scientists? How can individuals effectively utilize this roadmap to progress...
0
by: Hystou | last post by:
There are some requirements for setting up RAID: 1. The motherboard and BIOS support RAID configuration. 2. The motherboard has 2 or more available SATA protocol SSD/HDD slots (including MSATA, M.2...
0
marktang
by: marktang | last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However,...
0
Oralloy
by: Oralloy | last post by:
Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers,...
0
jinu1996
by: jinu1996 | last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven...
0
tracyyun
by: tracyyun | last post by:
Dear forum friends, With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each...
0
agi2029
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing,...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.