New to Matlab, need help on first script

First, I have never used Matlab previously, and the only software similar to this which I have used is Maple, so I may be hard to help at first but I usually pick things up quickly, so thanks for your patience...(and I have taken some java previously)

Here is the problem

"Write a MATLAB program that receives logical inputs s, e, and f (for the sign, exponent, and the fraction mantissa in the IEEE 754-2008 64 bit standard format) and outputs the corresponding decimal number. Test your program on various inputs including:

While I don't want the exact script to solve this, i would like to know which direction I should go...so here is my thinking

Start with a code that asks for logical input for s,e,f values. So this is what I got..

**UPDATE NOW I"M HERE****

s = input('What is the s-value?         ');
e = input('What is the e-value?         ');
f = input('What is the f-value?         ');
s1 = bin2dec('s'); 
e1 = bin2dec('e');
f1 = bin2dec('f');

x = (-1)^s1 * 2^(e1-1023) * (1+f1)

disp('x')

************************

I'm getting this error,

******************

??? Error using ==> bin2dec at 54
Binary string may consist only of characters 0 and 1

Error in ==> Homework at 9
s1 = bin2dec('s');

***********

Does anyone now why...as a test I put in s=1, e=1, f=1

[Dishant Arora]

you have inbuilt function 'bin2dec' for the conversion.

[Image Analyst]

Hmmm... not as robust and user friendly as the code I offered you. Any reason why you don't like dialog boxes and validating/checking your user's inputs?

Answer 1

[Image Analyst]

Here's a little snippet you may study and start with:

% Ask user for a number.
defaultValue = 45;
titleBar = 'Enter a value';
userPrompt = 'Enter the integer';
caUserInput = inputdlg(userPrompt, titleBar, 1, {num2str(defaultValue)});
if isempty(caUserInput),return,end; % Bail out if they clicked Cancel.
integerValue = round(str2num(cell2mat(caUserInput)));
% Check for a valid integer.
if isnan(integerValue)
    % They didn't enter a number.  
    % They clicked Cancel, or entered a character, symbols, or something else not allowed.
    integerValue = defaultValue;
    message = sprintf('I said it had to be an integer.\nI will use %d and continue.', integerValue);
    uiwait(warndlg(message));
end

[Kevin]

I'm actually experimenting both here...Just trying to learn as much as possible. I used the help command and got this, which i think is similar to yours...I really like the dialog window, it just seemed more complicated. I can't figure out how to store the input from the user. Any ideas?

 prompt={'What is the s-value?','What is the e-value','What is the f-value'};
   name='Please enter the values';
   numlines=1;
   defaultanswer={' ',' ',' '};

   options.Resize='on';
   options.WindowStyle='normal';
   options.Interpreter='tex';

   answer=inputdlg(prompt,name,numlines,defaultanswer,options);

[Kevin]

Also, for the code you supplied, if i try that, i don't get an error message for entering something other than an integer

Answer 2

[Dishant Arora]

s = input('What is the s-value? ');
e = input('What is the e-value? '); 
f = input('What is the f-value? ');
s1=bin2dec(num2str(s));
e1 = bin2dec(num2str(e));
f1 = bin2dec(num2str(f));
x = (-1)^s1 * 2^(e1-1023) * (1+f1);

[Dishant Arora]

logical inputs must be class char, num2str converts s,e,f into strings. or you can directly input strings to s,e,f

[Kevin]

So, where is my problem here... When i say "s = input('What is the s-value? ');" Does that mean I'm inputting a number? Or does that come in as a string value, which i then need to convert.? Thanks for your help

[Dishant Arora]

when you write s = input('What is the s-value? '), user can input any thing, a string, number, so that's need to be taken care of. if you want it to be read as string you must enclose input in quotes(''), other wise matlab considers it as a number.

where as s = input('What is the s-value? ','s'), reads input as string only.

[Kevin]

For some reason I now get this error

    ??? Error using ==> input
The second argument to INPUT must be 's'.

Error in ==> Homework at 17 e = input('What is the e-value? ','e')

for my code

s = input('What is the s-value? ','s')

e = input('What is the e-value? ','e')

f = input('What is the f-value? ','f')

[Dishant Arora]

it should be

s = input('What is the s-value? ','s')
e = input('What is the e-value? ','s');
f = input('What is the f-value? ','s');

's' here means character string input.

[Kevin]

:) makes sense