fopen 'w' not writing

The following is my code. I seem to not be able to write the code into the phone.txt file. can anyone tell me where my error is? phonenos.csv is an file with 3 lines of 10 digits, reminiscent of a phone number without the dashes or parentheses. this code will write them into the format (xxx) xxx-xxxx

format long g
fid=fopen('phonenos.csv','r');
fid2=fopen('phone.txt','w');

for i=1:3
    phonenos=fgetl(fid);
    area=phonenos(1:3);
    next3=phonenos(4:6);
    last4=phonenos(6:9);
    phonenos=['(' area ') ' next3 '-' last4];

end

close=fclose(fid);
close2=fclose(fid2);

type phone.txt

Answer 1

[Orion]

You forget a fprintf(fid2,... line, so you are not writing anything with this code, just open and close the phone.txt file.

you need to complete this

fid=fopen('phonenos.csv','r');
fid2=fopen('phone.txt','w');
for i=1:3
    phonenos=fgetl(fid);
    area=phonenos(1:3);
    next3=phonenos(4:6);
    last4=phonenos(6:9);
    phonenos=['(' area ') ' next3 '-' last4];

    fprintf(fid2,................) % line to complete

end
close=fclose(fid);
close2=fclose(fid2);

[Image Analyst]

I'd use the t option because they're text files.

fid = fopen('phonenos.csv', 'rt');
fid2 = fopen('phone.txt', 'wt');

From the help for fopen:

To open files in text mode, attach the letter 't' to the permission argument, such as 'rt' or 'wt+'.

Answer 2

[David Phung]

Thank you, it works like a charm!