C / C++ / MFC

31-Jul-03 5:16

How can I copy a 2dim array?

thanks,
Steven

John M. Drescher31-Jul-03 5:27

31-Jul-03 5:27

Dynamic or Static??

John

johnstonsk31-Jul-03 5:42

31-Jul-03 5:42

Static.

sj

John M. Drescher31-Jul-03 5:44

31-Jul-03 5:44

I believe you can use memcpy in the same way you did as a 1 dimensional array.

John

Ryan Binns31-Jul-03 5:47

31-Jul-03 5:47

If it's the same as in your previous question, but in two dimensions, then you can do the same thing

char a1[10][10];
char a2[10][10];
memcpy(a1, a2, sizeof(a2));

Hope this helps,

Ryan

"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

johnstonsk31-Jul-03 5:54

31-Jul-03 5:54

Thanks,

I must be doing something ese wrong, because it keeps crashing.

I'll keep pecking Smile | :)

Ryan Binns31-Jul-03 5:57

31-Jul-03 5:57

johnstonsk wrote:
must be doing something ese wrong, because it keeps crashing.

Post the array declarations, and the code that causes the crash, and we'll see what we can do for you Smile | :)

Ryan

"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

johnstonsk31-Jul-03 6:26

31-Jul-03 6:26

The error I get is there is a call to undefined function memcpy()
I included the string.h
Can this function only copy chars or strings?

The program that I have reads data from a pci card and puts it in the structures below:

This data gets updated 2 times a second.

struct TSimHeader
    {
	char   Name[47][20];
	char   Unit[47][20];
	double Min[47];
	double Max[47];
	int SignalCount;
	int SimStatus;

    }static TSimHeader_arr[10];


    struct TSimSignal
    {
       	double Value[47];
	double TimeStamp;

    }static TSimSignal_arr[10];

I have added a new feature to the program that will allow the recording of data.
This will be done by writiing the data to a *csv file so it can be read in excel.

Since the data in the structures is getting updated 2 times a second I thought that it would be good to just make a new array and copy the data to the array so, if the user wanted to start recording the data it would be there ready to start recording. That is why I call the copyData() function everytime the data is updated.

I also created arrays that are of the same type and size of the ones in the struct

char   name[47][20];
char   unit[47][20];
double min[47];
double max[47];
double value[47];

Below is the copyData() function:

void RFMAccess::copyData(){

    if(firstTime1){
        memcpy(pflight_data->name, TSimHeader_arr[0].Name,
                    sizeof(TSimHeader_arr[0].Name));
        memcpy(pflight_data->unit, TSimHeader_arr[0].Unit,
                    sizeof(TSimHeader_arr[0].Unit));
        memcpy(pflight_data->min, TSimHeader_arr[0].Min,
                    sizeof(TSimHeader_arr[0].Min));
        memcpy(pflight_data->max, TSimHeader_arr[0].Max,
                    sizeof(TSimHeader_arr[0].Max));
    }
    if(!firstTime1){
         memcpy(pflight_data->value, TSimSignal_arr[0].Value,
                    sizeof(TSimSignal_arr[0].Value));
    }

}

Then I call the writeData() function from another class that writes teh data in the copied arrays to a file.

Here is the writeData()

void LogData::writeData(){
     Sleep(350);
     int count;
     if(firstTime){
        fout<<"flight_data,";
        for(int i=0; i<RFMAccess::TSimHeader_arr[0].SignalCount; i++){
            if(passes == 1){                 //from passes 1 to 4 the data only gets written once
                if(i == 0){
                    fout<<aflight_data->name[i]<<endl;
                    passes++;
                    writeData();
                }
                else
                    fout<<aflight_data->name[i]<<",";
            }
            else if(passes == 2){
                if(i == 0){
                    fout<<aflight_data->unit[i]<<endl;
                    passes++;
                    writeData();
                }
                else
                    fout<<aflight_data->unit[i]<<",";
            }
            else if(passes == 3){
                if(i == 0){
                    fout<<aflight_data->min[i]<<endl;
                    passes++;
                    writeData();
                }
                else
                    fout<<aflight_data->min[i]<<",";
            }
            else if(passes == 4){
                if(i == 0){
                    fout<<aflight_data->max[i]<<endl;
                    firstTime = false;
                    writeData();
                }
                else
                    fout<<aflight_data->max[i]<<",";
            }
        }
    }
    if(!firstTime && (aflight_data->log  == true)){     //this data gets writen until the user says stop
        for(int j=0; j<RFMAccess::TSimHeader_arr[0].SignalCount; j++){
            if(j == 0){
                fout<<aflight_data->value[j]<<endl;
                writeData();
            }
            else
                fout<<aflight_data->value[j]<<",";
        }
    }

}

Sorry fo rall the code snips, I just wanted to make sure that the problem was understood.

Thanks for the intrest,
Steven Smile | :)

KeithD31-Jul-03 6:36

KeithD

31-Jul-03 6:36

are you sure you're including string.h in the file that uses memcpy? that error you're getting means it can't find the memcpy function at all.

johnstonsk31-Jul-03 6:46

31-Jul-03 6:46

Yes it is definetly in there.

The program will compile but, if I run the debugger on the memcpy() function it reads that the function is undefined.

Strange.

Steven

KeithD31-Jul-03 7:32

KeithD

31-Jul-03 7:32

well you can try a double for loop to copy the data.

for(int i=0; i<47; i++)
for(int j=0; j<20; j++)
old[i][j] = new[i][j];

i wouldn't recomend that (memcpy should work) but at least you can get your debugger going again to examine the memory. if it still crashes then you have some other problem =/

John M. Drescher31-Jul-03 7:55

31-Jul-03 7:55

johnstonsk wrote:
I run the debugger on the memcpy() function it reads that the function is undefined.

Confused | :confused:

What do you mean it is undefined?? If it compiled then it is defined... You mean that the debugger will not step into the memcpy() function? If so you do not have the correct symbols installed..

John

armentage31-Jul-03 9:33

armentage

31-Jul-03 9:33

johnstonsk wrote:
How can I copy a 2dim array?

CIS101 [Introduction to Computer Science]

Hello - from a newbie

Paul Southwick31-Jul-03 4:53

Paul Southwick

31-Jul-03 4:53

Just wanted to extend to all members a hello and to let you know that I am working with MS VC++ 6.0. I have written a database application for my wife's orchid hobby in MS BV 6.0 and hope to duplicate that effort - as I said, I'm new to c++ and to this board. Hello, and I'm looking forward to learning from all of you. Until I'm more comfortable - I will lurk...;)

Paul

Ryan Binns31-Jul-03 5:05

31-Jul-03 5:05

Welcome to CP, Paul Smile | :)

We hope your stay is a pleasant one. Please don't hesistate to ask for assistance should any problem arise. Roll eyes | :rolleyes:

Do I sound like a hotel owner? Unsure | :~

Glad to see you have woken up and switched from VB to VC++ Poke tongue | ;-P

Yes, VB bashing is fairly common here Smile | :)

Check out the C++ FAQ by Michael Dunn (there's a link at the top of the page) - it's got lots of great stuff that might help while you're getting started.

Enjoy, and don't hesistate to ask questions; we're a pretty nice bunch of people usually Smile | :)

Ryan

"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

John M. Drescher31-Jul-03 6:08

31-Jul-03 6:08

Ryan Binns wrote:
we're a pretty nice bunch of people usually

Yes, as long as you don't ask Programming questions in the Lounge or submit an article that it looks like a four year old wrote you should be ok...

John

Ryan Binns31-Jul-03 6:12

31-Jul-03 6:12

John M. Drescher wrote:
Yes, as long as you don't ask Programming questions in the Lounge or submit an article that it looks like a four year old wrote you should be ok...

Exactly Smile | :)

Ryan

"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

-- NA --31-Jul-03 5:23

-- NA --

31-Jul-03 5:23

Just going to re-iterate what Ryan has already said Smile | :)

Firstly welcome to CP, enjoy your stay! Smile | :)

There are many knowledgeable people here, willing to help anyone that asks. Don't hesitate! Smile | :)

I'm also really glad to hear you switched from VB to C++! Excellent decision! Big Grin | :-D

I'll keep quiet now and leave you to lurk Poke tongue | ;-P

Paul

Tiny problem with said member has been corrected.
Chris Maunder

modified 18-Jul-18 11:59am.

Jim Crafton31-Jul-03 7:59

Jim Crafton

31-Jul-03 7:59

Paul Southwick wrote:
in MS BV 6.0

That's the new MS Bisual Vasic programming language that just came out, right? Smile | :)

Seriously though, welcome to CP !

¡El diablo está en mis pantalones! ¡Mire, mire!

Real Mentats use only 100% pure, unfooled around with Sapho Juice(tm)!

simple memcpy() question

johnstonsk31-Jul-03 4:37

31-Jul-03 4:37

I have a number a different arrays.

double t1[10];
char   t2[10];
...

double cpT1[10];
char   cpT2[10];

If I make a array of the same size to copy into can I use the memcpy() function like this?

memcpy(cpT1, t1, sizeof(t1));  //Im thinking that the sizeof(t1) will return the size of the array t1 with all the data in it.

memcpy(cpT2, t2, sizeof(t2));

Or should I create a function that I pass the amount to the memcpy() function?
If So how can I make it so that I can pass any array to the function?

Thanks,
steven

Cedric Moonen31-Jul-03 4:44

Cedric Moonen

31-Jul-03 4:44

If the array are statically created (like in your example), that will work, otherwise not !

johnstonsk31-Jul-03 4:49

31-Jul-03 4:49

thanks,
sj

John M. Drescher31-Jul-03 4:46

31-Jul-03 4:46

memcpy(cpT1, t1, sizeof(t1));  //Im thinking that the sizeof(t1) will return the size of the array t1 with all the data in it.
memcpy(cpT2, t2, sizeof(t2));

This will work fine.

John

johnstonsk31-Jul-03 4:50