Why does my code not function properly?

Elimit= 0.001;
nlimit= 10000;
n=0;
prompt= 'input a value for a :   ';
a=input (prompt);
prompt= 'input a value for b:    ';
b=input(prompt);
f(1) = 16*(a)^2 + 3*(a)-1;
f(2) = 16*(b)^2 + 3*(b)-1;
if f(1)==0
            fprintf('The root is %f =     ', a);
else    
            if f(2)==0
                fprintf('The root is %f =    ',b);
            end
end
while (f(1)*f(2)>0)
   prompt = 'Please insert a new value for b:     ';
   b=input (prompt);
        if f(1)==0
            fprintf('The root is %f =     ', a);
            if f(2)==0
                fprintf('The root is %f =    ',b);
            end
        end
end 
        c = a+b/2;
        Ere = abs(b-a/c);     
while (Ere > Elimit && n< nlimit)
    n = n+1;
    f(3) = 16*(c)^2 + 3*(c)-1;
    if f(3)==~0
     fprintf ('The root is %f=      ', c);
    return
    else if f(3) * f(2)>0
            b=c;
        else
            a=c;
        end
    end  
end

[Stephen23]

What does "Why does my code not function properly" actually mean? If you actually write what the code does that you do not expect, then we do not have to rely on our mind-reading skills.

Does "not function properly" mean one of these?:

• the code made my computer explode
• the code deleted the internet
• the code produced an incorrect result
• the code crashes my computer
• the code results in an error message (and here it is...)
• the code does not run when I click on my GUI button that I have not told you anything about...

http://www.mathworks.com/matlabcentral/answers/728-how-do-i-write-a-good-question-for-matlab-answers

http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

It also helps us (and you too!) if you write tidy, readable code, with consistent indentation. And then formatting this properly that we can follow your code too:

http://www.mathworks.com/matlabcentral/answers/13205-tutorial-how-to-format-your-question-with-markup

[John D'Errico]

Why do you think it is not functioning "properly" Define proper, and say what it does that is not proper please? Make it easy for someone to answer your question, rather than forcing them to run your code, then figure out what they think it should have done. As it is, a quick glance at the code shows any number of issues that COULD cause problems.

Answer 1

[Joseph Jennings]

Dania,

After carefully reviewing your code, one thing I would like to point out is that declaring a variable F(1) or F(2) or F(3) should be done differently in your code. Now I could be mistaken so let me apologize upfront if I am wrong, to the best of my knowledge you should create a single variable F=[equation 1, equation 2, equation 3] and then call them by saying F(1) or F(2) or F(3), in matlab when you use a variable name with parenthesis the way that you have done it, matlab is looking for the 1st, 2nd or 3rd entry in the variable F. If you do not wish to create an array and call each entry in the array back you could simply call each one F1 F2 and F3. However, when you write "if f(2)==0" matlab is interpreting that as "if the second entry in the variable f is equal to exactly 0" if that is what you meant then you need to create an array with 3 entries in order to get your code to function the way it is written.

I hope this helps and again I apologize in advance is this wasn't what you were looking for however, the question as stated by the previous responses needs to be better written so others can understand what you're really asking. best of luck