MESSAGE
| DATE | 2008-08-30 |
| FROM | Ruben Safir
|
| SUBJECT | Subject: [NYLXS - HANGOUT] Re: multi-dim arrays in c
|
On Fri, Aug 29, 2008 at 08:16:35PM -0400, Ruben Safir wrote:
> On Fri, Aug 29, 2008 at 05:43:40PM -0400, Stephen Adler wrote:
> > Guys,
> >
> > I've got a standard c coding question which has been nagging me for a
> > while and I was wondering what you guys may think or have the correct
> > solution to this problem....
> >
> > Lets say I have a 2 dim array of data and the dimension sizes can change
> > depending on the specific data set. I can read in the x and y dimensions
> > from a file, then read in the x*y elements of the data a populate a
> > memory area x*y*elementsizeinbytes with the data. But now I want to
> > access the data. Without doing pointer arithmatic, is it possible to use
> > the standard [][] notation somehow?
> >
> > for example
> >
> > int *data;
> > x=getXDim();
> > y=getYDim();
> > data=(int *)malloc(x*y*sizeof(int));
> > readInData(x,y,data);
> > printf("Middle data element is %d\n",data[y][x]);
> >
> > but I know that that data[y][x] will barf on the compiler because the
> > compiler has no way of knowing what the y size of the "y" dimension is...
> >
> > Any suggestions on how to use the N-dimensional bracket notation in this
> > situation?
> >
> > Thanks.
> >
>
nclude
#include
int **my;
int x = 100;
int y = 500;
int i = 0;
int j = 0;
int k = 0;
int main(){
my = (int **)malloc(x * sizeof(int*));
for(; i my[i] = (int *)malloc(y * sizeof(int *));
}
for(i = 0; i < x; i++)
for(j=0; j my[i][j] = i + j;
printf ("i=> %d j=> %d slot: %d ==> %d\n",i,j,k,my[i][j]);
k++;
printf("Hello\n");
}
printf("%d", my[0][5]);
return 0;
}
>
> Yes, in fact int main() does this using char** as a parameter.
>
> I have a sample worked out on my laptop which I can't put on my
> jobs network, but when I get home I'll post an example.
>
> Ruben
>
>
> >
> > --
> > This message has been scanned for viruses and
> > dangerous content by MailScanner, and is
> > believed to be clean.
> >
> > _______________________________________________
> > Discuss mailing list
> > Discuss-at-blu.org
> > http://lists.blu.org/mailman/listinfo/discuss
>
> --
> http://www.mrbrklyn.com - Interesting Stuff
> http://www.nylxs.com - Leadership Development in Free Software
>
> So many immigrant groups have swept through our town that Brooklyn, like Atlantis, reaches mythological proportions in the mind of the world - RI Safir 1998
>
> http://fairuse.nylxs.com DRM is THEFT - We are the STAKEHOLDERS - RI Safir 2002
>
> "Yeah - I write Free Software...so SUE ME"
>
> "The tremendous problem we face is that we are becoming sharecroppers to our own cultural heritage -- we need the ability to participate in our own society."
>
> "> I'm an engineer. I choose the best tool for the job, politics be damned.<
> You must be a stupid engineer then, because politcs and technology have been attached at the hip since the 1st dynasty in Ancient Egypt. I guess you missed that one."
>
> © Copyright for the Digital Millennium
>
> --
> This message has been scanned for viruses and
> dangerous content by MailScanner, and is
> believed to be clean.
>
> _______________________________________________
> Discuss mailing list
> Discuss-at-blu.org
> http://lists.blu.org/mailman/listinfo/discuss
--
http://www.mrbrklyn.com - Interesting Stuff
http://www.nylxs.com - Leadership Development in Free Software
So many immigrant groups have swept through our town that Brooklyn, like Atlantis, reaches mythological proportions in the mind of the world - RI Safir 1998
http://fairuse.nylxs.com DRM is THEFT - We are the STAKEHOLDERS - RI Safir 2002
"Yeah - I write Free Software...so SUE ME"
"The tremendous problem we face is that we are becoming sharecroppers to our own cultural heritage -- we need the ability to participate in our own society."
"> I'm an engineer. I choose the best tool for the job, politics be damned.<
You must be a stupid engineer then, because politcs and technology have been attached at the hip since the 1st dynasty in Ancient Egypt. I guess you missed that one."
© Copyright for the Digital Millennium
|
|
