Output argument "cost" (and maybe others) not assigned during call to "C:\Users\​NIck\Docum​ents\MATLA​B\calcCall​.m>calcCal​l".

Can anyone tell me what I"m doing wrong, I've read other threads and can't figure this out. I made a function calcCall to determine the cost of a call during given times of the day. tod = time of day; doc = duration of call. I created a new function window and I think thats where the problem lies because when I take the same code and write it on main, it works fine. So there is a disconnect between main that the function call I guess. Thanks for your help.

 in main:

%%LAB6 HMWK
% DESCRIPTIVE TEXT

tod = input('What time of day was the call made, day evening or night?','s');

doc = input('How long did the call last?'); 

ans = calcCall('tod',doc);

fprintf('The cost of the call is %.2f, ', ans)

the function file:

function [ cost ] = calcCall(tod,doc) %must save this function with name 'calcCall'
%UNTITLED Summary of this function goes here
%   Detailed explanation goes here

switch tod
    case {'day' 'Day' 'DAY' 'd' 'D'}
        if (doc > 0 && doc < 10)
            cost = ceil(doc)*.10;
        elseif (doc >= 10 && doc < 30)
            cost = 1 + ceil(doc)*.08;
        else
            cost = 2.60 + ceil(doc)*.06;
        end
    case {'evening' 'Evening' 'EVENING' 'e' 'E'}
        if (doc > 0 && doc < 10)
            cost = ceil(doc)*.07;
        elseif (doc >= 10 && doc < 30)
            cost = .70 + ceil(doc)*.05;
        else
            cost = 1.70 + ceil(doc)*.04;
        end
    case {'night' 'Night' 'NIGHT' 'N' 'n'}
        if (doc > 0 && doc < 10)
            cost = ceil(doc)*.04;
        elseif (doc >= 10 && doc < 30)
            cost = .04 + ceil(doc)*.03;
         else
            cost = 1.00 + ceil(doc)*.02;
        end        
end

 end

Command line:

EDU>> clear EDU>> which calcCall C:\Users\NIck\Documents\MATLAB\calcCall.m EDU>> which HMWKLab6 C:\Users\NIck\Documents\MATLAB\HMWKLab6.m EDU>>

Answer 1

[Brendan Hamm]

In the function you expect the variable called tod to assume one of the values in {'day','evening','night'}, along with alternative ways of entering these 3 cases.

In your call to the function you pass it the character array tod = 'tod'

ans = calcCall('tod',doc);
% should read
ans = calcCall(tod,doc);

Just remove the the quotation marks and you will pass in the variable tod which has the value from the input.

Note: If you have a discrete number of choices, as in your case, use the menu() function instead. I also wouldn't assign to ans as this can be overwritten way too easily.

Answer 2

[Sean de Wolski]

You're passing in the string literal 'tod'. Since none of the cases in the switch-case tree have 'tod' as an option, cost never gets assigned and you get the error you're seeing.

You probably want to call the function like this:

calcCall(tod,doc);

Note the lack of single quotes around tod which indicates it's a variable not a string.

Another thing to do is when you have a switch case statement, I usually add an otherwise (i.e. if no cases were met). This makes debugging like this easier

otherwise
   error('This shouldn''t happen')