Function to count the number of characters in a text file

Hi

I've wrote the following code so far, but I'm having the problem that sum(charnums) returns the latest given value of charnums and doesn't sum over them. (as I can tell the code would, but I'm quite new to matlab and can't think how to write it with some index, for example i've tried charnums(oneline)=b2(oneline)... etc , as the 'oneline' is what is being iterated over I thought... but than it says dimensions exceed ... error .

many thanks

function[charnum]=liness(fname,character) 
fid=fopen(fname,'rt')


if ( fid<0)
    charnum=-1
    return
     
else

  a=findstr(oneline,character);
[b1,b2]=size(a);
charnums=b2

while ischar(oneline)
    fprintf('%s',oneline)
      a=findstr(oneline,character);
[b1,b2]=size(a);
charnums=b2
  oneline=fgets(fid)
     
end
end
charnum=sum(b2)
fclose(fid)
end

Answer 1

[Walter Roberson]

  a=findstr(oneline,character);

Your assignment requires you to determine that character is really a valid character and return -1 if it is not.

You have not defined oneline at that point.

  [b1,b2]=size(a);
charnums=b2

hint: numel()

    fprintf('%s',oneline)

You are not asked to display the content of oneline -- but it would not hurt to do so for debugging purposes, as long as you remove that afterwards.

    charnums=b2

You are overwriting charnums each iteration of the while loop.

You also never use the value of charnums

    charnum=sum(b2)

You overwrote all of b2 each iteration of the while loop.

Hint:

    total = total + current_value

Also, your current logic has a problem in the case where the file exists and is readable but is completely empty, as the first read from such a file would immediately return an indication of end-of-file, and you should not be asking about the size of that end-of-file marker.

[Sara Ismail-Sutton]

hi many thanks for your reply. i have no idea how to incorporate numel , i want to label things by index, from a google this counts the indexes or? thanks the other corrections I did notice, re. the b2 and charnums and do intend to put the semi-colon back in, it was for debugging purposes.

[Sara Ismail-Sutton]

Hint: total = total + current_value

Yes I want to implement somehting like this but I do not know how since I don't know how to write b2 as a function of the index , which i want to be labelling each 'oneline' I guess.. thanks

[Walter Roberson]

counter = 0;

while whatever
    do something
    counter = counter + 1;
    [b1, b2(counter)] = size(a);
end

and then afterwards you can sum the vector b2.

However, this is really unnecessary and inefficient. Consider

counter = 0;
while whatever
    do something
    [b1, b2] = size(a);
    counter = counter + b2;
end

[Sara Ismail-Sutton]

okay many thanks!!