error in arrays line 7

function V = fuelvol2(h)
   global r H L
   
validInput = true;                             %to test each value in the vector h is valid

for i = 1:length(h)
    Nh = h(i);
    if (Nh < 0 && (Nh > h + 2*r))
        validInput = false;
        break;
    end
end

if validInput == true    % if it is valid vector the calculate volume using vectorized operations 
    d = h-H;
    V = 2*r*L*H + (r^2 * acos((r-d)/r) - (r-d).*sqrt(2*r.*d -d.^2))*L;
    
else 
    disp("one of more values in vector his/are valid ")
    
end

I keep getting tis error each time i try to run the code

Not enough input arguments.

Error in fuelvol2 (line 7)
for i = 1:length(h)

[Adam Danz]

It sounds like you're running the function without an input. You must provide an input "h", to the function.

[Walter Roberson]

When you are running the function by clicking the green Run button, what is your assumption about how MATLAB should know what the value of h is ?

[Ronald Aono]

hese are my inputs from the command window

% we will now define our terms 
r = 0.95;  H = 2.0;  L = 5.0;                        % this are all in ft
h = 0:(H + 2*r); Nh = Length(h);
V = fuelvol1(h);
vol1 = zeros(V,Nh);
for j = 1:Nh
    vol1(:, j) = fuelvol1(h);
    
end

still getting the same error

main_fuelvol12
Undefined function or variable 'Length'.
Error in main_fuelvol12 (line 6)
h = 0:(H + 2*r); Nh = Length(h);

[KALYAN ACHARJYA]

Nh=length(h);
%....^ small letter

[Adam Danz]

Function calls are case sensitive. There is no matlab function named Length() but there is a function with the lower case length(). However, it's recommended to use numel() instead of length().

[Ronald Aono]

Thank you for the length error, i appriciate it . how do i clear this error to, it keeps creeping up

Operands to the || and && operators must be convertible to logical scalar values.

Error in fuelvol1 (line 7)
if (h>=0) && (h <= (H + 2*r))

Error in main_fuelvol12 (line 7)
V = fuelvol1(h);

Answer 1

[Adam Danz]

It's getting hard to follow the discussion because we're jumping around between different similarly named functions. fuelvol1, fuelvol2, main_fuelvol12.

This error appears to be in fuelvol1 but we don't have access to that function. However, I think the error can be fixed by replacing && with &.

Answer 2

[Walter Roberson]

for i = 1:length(h)
    

So you are expecting h to be a non-scalar.

    if (Nh < 0 && (Nh > h + 2*r))

You add the non-scalar h to something and compare it to the scalar Nh, producing a non-scalar result on the right hand side of the && . However, the && operator can only be used when both sides are scalars.

Changing to & is not the correct solution. The correct solution is to stop using single-letter variable names that differ only in upper versus lower case, because it is too easy to get the wrong variable name. You do not want h there, you want H .

In your other question, H and 2*r were both positive, and Nh > some_positive_value cannot be simultaneously true with Nh < zero.

[Adam Danz]

Just curious, from where did you get "for i = 1:length(h)"? I see it in fuelvol2() but the error is in fuelvol1() which we don't have access to, unless I'm missing something.