problem read data from text file into two-dimensional array in c++

for a array generally the order will be
A[0][0]
A[0][1]
...
A[0][N]
A[1][0]
A[1][1]
...
A[1][N]
...
A[N][0]
...
A[N][N]

can this be the problem??? I have 8 columns 5000 rows in the textfile does it matter how to define the array??  short leads[7][4999]; or short leads [4999][7]??

with your suggestion amit2000 the data will not be entered correctly in the array!

OK...that means u have 5000lines
Hope u want each line to be in Array[N]...
So u have to make the initialization as short leads[5000][8]; //max length

print each column to see whether it is getting all chars from the file...

Shouldn't this,...

short leads[7][4999];

Be defined like this?

short leads[4999][7];

it is getting the numbers from the file correctly. It is easier for code later on to have it like [7][4999] this should not be a problem it think??

evilrix:

this array contains samples for 8 recorded signals and I have to put all the samples from each of the signals in another structure later on like:

pRaw->samples[leadNum] = leads[i];

therefore I want it like [7][4999]

Sorry.........
I understand it wrongly...
Let me explain again....
As you have "while (getline(myfile, line))" loop first, that means this loop is going to run 5000times
And the inner loop will run for 8 times..

I will get back soon......

amit2000: yes thats right but this is correct in my code i think! leads[a][b]

>> therefore I want it like [7][4999]

Well, when you size an array it's [rows][cols] and this is how you are using it.

leads[a][b] = 100;//(short) atoi(token.c_str());

You increment 'a' multiple times for 'b' but you are defining it as

[7][4999]

so you are causing a buffer overrun.

evelrix thats not completely clear to me:

"You increment 'a' multiple times for 'b'" ??

For each column (\t) i am incementing a and for each row i am incrementing b that is correct isn't it??

have you checked how many times each loop is running?

>> "You increment 'a' multiple times for 'b'" ??

I am saying that although you have defined the array as ...

short leads[7][4999];

The way you are indexing it means it should be defined thus...

short leads[4999][7];

Look at your nested loops and where you increment 'a' and 'b'

        while (getline(myfile, line))
        {
          iss << line;
          while (getline(iss, token, '\t'))
          {
                 leads[a][b] = 100;//(short) atoi(token.c_str());
                 a++;
          }
          iss.clear();
          b++;
          a=0;
        }

For every outer iteration you increment 'b' and for every inner iteration you increment 'a' so 'a' is incremented a whole bunch of times for every time 'b' is incremented and you index the array [a][b] but it's defined as [7][5000] so you will end up overrunning the buffer.

mmm??

a is reset to zero everytime (for every new line in the textfile) The columns in the file are tab delimited and the rows are \n delimited. The outer loop are the rows the inner loop the columns.

Generally arrays are defined as array[rows][cols].......in your case rows=no of lines=5000 and cols=no of columns=8, try define it as leads[5000][8] and try once.

>>  try define it as leads[5000][8] and try once.

I have already said that http:#25447150

Ok that helps infinity08.

The stupid error was that it should have been short leads[8][5000] instead of leads[7][4999]. I mixed up the fact that in the definition of the array size the actual number of rows should be defined not -1 which is only true for the index (0...7, 0...4999).

Further I understand that normally an array is [5000][8] in this case but I have reasons to do it the other way around because of a assignment later: pRaw->samples[leadNum] = leads[i];

which assigns a whole column by pointer to another structure

>> I mixed up the fact that in the definition of the array size the actual number of rows should be defined not -1 which is only true for the index (0...7, 0...4999).

Precisely :)


>> Further I understand that normally an array is [5000][8] in this case but I have reasons to do it the other way around because of a assignment later

Understood ;)