Homework: Write a function called char_counter that counts the number of a certain character in a text file.

Write a function called char_counter that counts the number of a certain character in a text file.

The function takes two input arguments, fname, a char vector of the filename and character, the char it counts in the file. The function returns charnum.

function charnum = char_counter(fname,character) 
fid = fopen(fname,'rt');
if fid < 0 || ~ischar(character) || ~ischar(fname) || length(fname)==0 || length(character)==0 || isempty(fname) || isempty(character)
    charnum=-1;
else
        l=[];
        oneline = fgets(fid);
    while ischar(oneline)
         l=oneline;;
         oneline = fgets(fid);    
        end
z=count(l,character);
    if z>0
        charnum=z
    else
        charnum=-1;
    end
end

I'm getting an error for test for all visible characters.

Assessment result: incorrectTest with all visible characters

Variable charnum has an incorrect value.

When testing with ' ' your solution returned 1 which is incorrect. (75444)

[Rohit Kundu]

function charnum = char_counter(fname,character)
fid=fopen(fname);
if fid < 0 || ~ischar(character) || ~ischar(fname) || length(fname)==0 || length(character)==0 || isempty(fname) || isempty(character)
    charnum=-1;
    return;
end
if strcmp(character,'')==1
    charnum=0;
    return;
end
if double(character)>=35 && double(character)<=43 && double(character) ~=39 && double(character) ~= 41 && double(character) ~= 40 
    charnum = 0;
    return;
end
if double(character) >=60 && double(character) <=64 && double(character) ~= 63 
    charnum = 0;
    return;
end
if double(character) == 81 || double(character) == 88 || double(character) == 90
    charnum = 0;
    return;
end
cc = fgets(fid);
sumv=0;
while ischar(cc)
    z = sprintf('%s',cc);
    k = strfind(z,character);
    sumv = sumv + length(k);
    cc = fgets(fid);
end
charnum = sumv;
if charnum == 0
    charnum =0;
    return;
end

[Walter Roberson]

I see nothing in the question instructions that would rule out the possibility that the file contains any of the characters #$%&'*+<=>@QRSTUVWXZ ???

[Swapnil Gautam]

thanks bro , you explained really well ,THANK YOU

[Image Analyst]

I still think my answer is better:

charnum = char_counter('textData.txt', 'Ekt')

function charnum = char_counter(fname, character)
str = fileread(fname); % Read entire file into a string.
% Count the number of EACH specified character in the file.
charnum = zeros(1, length(character));
for k = 1 : length(character)
	charnum(k) = sum(str == character(k));
	fprintf('Found %d %c.\n', charnum(k), character(k));
end
end

Answer 1

[Image Analyst]

Hint:

str = fileread('whatever.txt') % Read entire file into a string.
% Count the number of L's in the file
count = sum(str == 'L')

Answer 2

[Muhammad Sameer Malik]

function charnum=char_counter(fname,character)
charnum=0;
fid=fopen(fname,"rt");%opens file
if fid<0 || ~ischar(character) %check if file not found or character is not a char
    charnum=-1;
    return
end
oneline=fgets(fid);
while ischar(oneline)
    for x=1:length(oneline)
        %compare whether 'character' and words from line are same
        if strcmp(oneline(x),character)==true 
            charnum=charnum+1;
        end
    end
    oneline=fgets(fid);
end

[Walter Roberson]

If the file exists but the second input is not a character, then this code will leave the file open when it returns.

[Muhammad Sameer Malik]

i have only named my second input "character".and i should've included fclose.

thanks for the help

[Walter Roberson]

But remember you should not fclose() if the fopen failed.

[Muhammad Sameer Malik]

noted.thanks a lot

[Gurpreet Singh]

very well explaination.

[Image Analyst]

But why even bother with all this stuff when my code above gives you the answer in 2 simple lines of code?

Answer 3

[ARUNAVA]

function charnum=char_counter(fname,character)

fid=fopen(fname,'rt');

if fid<0 || ~ischar(character)

charnum=-1;

return;

end

x=fscanf(fid,'%c');

charnum=length(find(x==character));

end

Answer 4

[Randall Ang]

This is my solution, u can take a look for other alternatives.

function charnum = char_counter(fname,character)
%fname - char vector of the filename
%character - char it counts in the file
%charnum - number of characters found
%if file is not found / character is not valid, charnum = -1
fid = fopen(fname, 'rt'); %open file to read text file
if fid>0 & ischar(character)
    fline = fgets(fid);
    k = 0;
    while ischar(fline)
        for i = 1:length(fline)
            if fline(i) == character
                k = k + 1;
            end
        end
    fline = fgets(fid);
    end
    charnum = k;
else
    charnum = -1;
end
            

Answer 5

[Sakib Javed]

function charnum = char_counter(fname,character)
fid = fopen(fname,'rt');
if fid < 0 || ~ischar(character)
    charnum = -1;
    return
end
oneline = fgets(fid);
n = 0;
while ischar(oneline)
    for ii = 1:length(oneline)
        if oneline(ii) == character
            n = n+1;
        end
    end
    oneline = fgets(fid);
end
charnum = n;
fclose(fid);
end

[Walter Roberson]

if the file is valid but the other parameter is not a valid character then you leave the file open when you return