not enough input arguments when using function handle

I write three functions, and one of them use the other two. When I run 'curve_p_16_1_1' and 'curve_p_16_1_2' alone, they work fine. However, when I run 'curve_p_16_1', it says 'Not enough input arguments.'. Could anyone help me to figure out the problem?

   function p = curve_p_16_1_1(t)
  %curve function of example 16, NACA 0012
  %inner air foil, upper part
  %INPUT:
  %t: parameter, [0,1], counterclockwise
  %OUTPUT:
  %p: [x y], point coordinate on curve

%x = sqrt(X) to avoid singularity at xmin
xmin = 0;
xmax = sqrt(1.008930411365);
y = @(x) 0.6*(0.2969*x-0.1260*x^2-0.3516*x^4+0.2843*x^6-0.1015*x^8);
syms s
dy = matlabFunction(diff(0.6*(0.2969*s-0.1260*s^2 ...
    -0.3516*s^4+0.2843*s^6-0.1015*s^8),s));
f = @(x) sqrt(1+dy(x).^2);
l = integral(f,xmin,xmax); %total curve length
g = @(x) integral(f,xmin,x)-(1-t)*l;
x = fzero(g,[xmin xmax]);
p = [x^2 y(x)];

function p = curve_p_16_1_2(t)
%curve function of example 16, NACA 0012
%inner air foil, lower part
%INPUT:
%t: parameter, [0,1], counterclockwise
%OUTPUT:
%p: [x y], point coordinate on curve

%x = sqrt(X) to avoid singularity at xmin
xmin = 0;
xmax = sqrt(1.008930411365);
y = @(x) -0.6*(0.2969*x-0.1260*x^2-0.3516*x^4+0.2843*x^6-0.1015*x^8);
syms s
dy = matlabFunction(diff(0.6*(0.2969*s-0.1260*s^2 ...
    -0.3516*s^4+0.2843*s^6-0.1015*s^8),s));
f = @(x) sqrt(1+dy(x).^2);
l = integral(f,xmin,xmax); %total curve length
g = @(x) integral(f,xmin,x)-t*l;
x = fzero(g,[xmin xmax]);
p = [x^2 y(x)];

function p = curve_p_16_1(T)

n = 2; %number of curves
for i = 1:n
    if T >= (i-1)/n && T <= i/n
        t = T*n-(i-1);
        str = ['@(t) curve_p_16_1_' num2str(i)];
        f = str2func(str);
        p = f(t);
    end
end

>> curve_p_16_1(0)
Not enough input arguments.

Error in curve_p_16_1_1 (line 18)
g = @(x) integral(f,xmin,x)-(1-t)*l;

Error in curve_p_16_1>@(t)curve_p_16_1_1

Error in curve_p_16_1 (line 9)
        p = f(t);

[Adam]

How are you running it? When you try to understand your error message yourself this is clearly important information!

[Stephen23]

@Susan_Y: please show us the complete error message. This means all of the red text. It would be useful to have some information on how you are calling these functions too.

[Susan_Y]

@Stephen Cobeldick, @Adam : I have updated the question with running information.

Answer 1

[per isakson]

Replace

str = ['@(t) curve_p_16_1_' num2str(i)];
f = str2func(str);
p = f(t);

in curve_p_16_1 by

p = feval( sprintf( 'curve_p_16_1_%1d', i ), t );

or

switch i
    case 1
        p = curve_p_16_1_1( t );
    case 2
        p = curve_p_16_1_2( t );
    otherwise
        error( 'Cannot find the function, "%s".' ...
            ,  sprintf( 'curve_p_16_1_%1d', i )  ) 
end

With one of these replacements the code returns a result

>> curve_p_16_1(0)
ans =
    1.0089    0.0000

The original code doesn't pass the argument, t, - it seems.

And see Debug a MATLAB Program

[Susan_Y]

Thank you for your answer. I use the second method and it works. However, why 't' won't be passed if using a function handle?

[per isakson]

The original code contains a "trivial" mistake, which I missed. The expression, &nbsp ['@(t) curve_p_16_1_' num2str(i)], &nbsp doesn't include t in the call of the function, curve_p_ ....

Try replacing

str = ['@(t) curve_p_16_1_' num2str(i)];

by

str = ['@(t) curve_p_16_1_', num2str(i), '(t)' ];

or

str = ['@curve_p_16_1_', num2str(i) ];

or

str = ['curve_p_16_1_', num2str(i) ];

All three makes the code work. The second is the "preferred" one.

The switch-case construct is the one that is easiest to debug.

[Susan_Y]

Thank you again. This is the true reason. I should be careful about the format of function handle.