How can I call a function that outputs text files?

I keep getting this error,

 ??? Error using ==> SECTOR
Too many output arguments.

for a function I created that outputs text files

The purpose of the function is that when the user types a corresponding number, MATLAB opens a file (fopen) which has been taken from a urlwrite function.

I am proceding the following way

 function fid = SECTOR(user_entry1)
 %
 %

 urlwrite('http://weather.noaa.gov/cgi-bin/fmtbltn.pl?file=forecasts/marine/coastal/am/amz722.txt','Anegada_Passage_Southward.txt'); % URL from forecast webpage
  urlwrite('http://weather.noaa.gov/cgi-bin/fmtbltn.pl?file=forecasts/marine/coastal/am/amz710.txt','Atlantic_Waters.txt');
  urlwrite('http://weather.noaa.gov/cgi-bin/fmtbltn.pl?file=forecasts/marine/coastal/am/amz732.txt','Caribbean_Waters.txt');
  urlwrite('http://weather.noaa.gov/cgi-bin/fmtbltn.pl?file=forecasts/marine/coastal/am/amz715.txt','Coastal_Waters_Northern_Culebra_NOT_EasternPR.txt');
  urlwrite('http://weather.noaa.gov/cgi-bin/fmtbltn.pl?file=forecasts/marine/coastal/am/amz742.txt','Coastal_Waters_Northwestern.txt');
  urlwrite('http://weather.noaa.gov/cgi-bin/fmtbltn.pl?file=forecasts/marine/coastal/am/amz725.txt','Coastal_Waters_Southern.txt');
  urlwrite('http://weather.noaa.gov/cgi-bin/fmtbltn.pl?file=forecasts/marine/coastal/am/amz745.txt','Coastal_Waters_Southwestern.txt');
  urlwrite('http://weather.noaa.gov/cgi-bin/fmtbltn.pl?file=forecasts/marine/coastal/am/amz741.txt','Mona_Passage_Southward.txt');
  urlwrite('http://weather.noaa.gov/cgi-bin/fmtbltn.pl?file=forecasts/marine/coastal/am/amz712.txt','Coastal_Waters_Northern.txt');
  urlwrite('http://weather.noaa.gov/cgi-bin/fmtbltn.pl?file=forecasts/marine/coastal/am/amz725.txt','Coastal_Waters_Southern_Vieques_Eastern.txt');

if user_entry1 == 1
fid=fopen('Anegada_Passage_Southward.txt');
 elseif user_entry1 == 2
    fid=fopen('Atlantic_Waters.txt');
elseif user_entry1 == 3
    fid=fopen('Caribbean_Waters.txt');
elseif user_entry1 == 4
    fid=fopen('Coastal_Waters_Northern_Culebra_NOT_EasternPR.txt');
elseif user_entry1 == 5
    fid=fopen('Coastal_Waters_Northwestern.txt');
elseif user_entry1 == 6
    fid=fopen('Coastal_Waters_Southern.txt');
elseif user_entry1 == 7
    fid=fopen('Coastal_Waters_Southwestern.txt');
elseif user_entry1 == 8
    fid=fopen('Mona_Passage_Southward.txt');
elseif user_entry1 == 9
    fid=fopen('Coastal_Waters_Northern.txt');
elseif user_entry1 == 10
    fid=fopen('Coastal_Waters_Southern_Vieques_Eastern.txt');
end

and the program file that calls the function goes like this,

 fprintf('Choose your forecast region by typing corresponding number:\n 1. Anegada Passage\n 2. Atlantic Waters\n 3. Caribbean Waters\n 4. Coastal Waters Northern | Culebra\n 5. Coastal Waters Northwestern\n 6. Coastal Waters Southern\n 7. Coastal Waters Southwestern\n 8. Mona Passage Southward\n 9. Coastal Waters Northern\n 10. Coastal Waters Eastern | Vieques\n');
  user_entry1=input('Input forecast: ');
  fid = SECTOR(user_entry1);

The output of the function must be a text file that later would go as an input in the variable 'fid'.

Can you please help?

NOTE: I am trying to format the code starting with 'if user_entry1 == 1...', but MATLAB does not let me.

[Walter Roberson]

Note that if the user enters something that is not 1, 2, 3, 4, 5, 6,7, 8, 9, or 10, then your code will not assign a value to "fid"

[jjlivestrong]

So what are you suggesting Walter? That I must specify that "in order for the program to work the input must be numbers from 1 - 10" in an fprintf command?

[Walter Roberson]

You should have code that assigns a value to "fid" even if the input is not one of those values. For example you could start with

fid = [];

[jjlivestrong]

Ok. Thank you.

Answer 1

[Image Analyst]

Add this code before the final end:

else
  warningMessage = sprintf('Error: you entered %d.\nThe allowed values are integers 1 through 10', user_entry1);
  uiwait(warndlg(warningMessage));
  fid = -1;

Then if you enter something not allowed, at least it will warn you.

[jjlivestrong]

Thank you Image Analyst. For some reason the moment I included your code the function worked.

As always, thank you very much and I wish both, Walter and you, to have a nice day

:)