Not enough input arguments (line 2)

Using the two functions I have defined so far (nonsense and printstuff) to run the for loop at the end. When running the for loop, it turns me back to the nonsense .m file and says 'not enough input arguments' (line2). Can anyone help with this?

NONSENSE:

function y=nonsense(x)

if mod(x,2) == 0

disp(x^2);

else

disp(0);

end

end

PRINTSTUFF:

function printstuff(func,values)

fprintf('Function evaluated at %d points: \n',length(values))

for q = 1:length(values)

fprintf('point %0.6f has value %0.6f\n',values(q),func(values(q)))

end

end

FOR LOOP:

printstuff(nonsense,[4 11 15 20])

for x = [4 11 15 20]

nonsense(x);

end

[Stephen23]

The function NONSENSE requires one input argument when it is called.

Here you are calling NONSENSE with zero input arguments:

printstuff(nonsense,[4 11 15 20])
%          ^^^^^^^^ calling with zero input arguments.

What do you expect that to achieve? It seems that you need to use a function handle.

Answer 1

[Stephen23]

You need to learn about function handles:

https://www.mathworks.com/help/matlab/function-handles.html

I also had to fix your code because you had not defined the output argument "y" inside NONSENSE().

%          v                       !!! define function handle !!!
printstuff(@nonsense,[4,11,15,20])

Function evaluated at 4 points: 
point 4.000000 has value 16.000000
point 11.000000 has value 0.000000
point 15.000000 has value 0.000000
point 20.000000 has value 400.000000

function y = nonsense(x)
if mod(x,2) == 0
    y = x^2;
else
    y = 0;
end
end

function printstuff(func,values)
fprintf('Function evaluated at %d points: \n',length(values))
for q = 1:length(values)
    fprintf('point %0.6f has value %0.6f\n',values(q),func(values(q)))
end
end

[meman4567]

Thanks for your answer. The ampersand did the trick (defining the function handle?)

Will definitely spend some time looking at the function handles: i'm very new to matlab so the more info I can take in the better :)

Not sure if info on this is in the documentation, but what exactly does the @ do?

[Stephen23]

"Not sure if info on this is in the documentation, but what exactly does the @ do?"

https://www.mathworks.com/help/matlab/function-handles.html

https://www.mathworks.com/help/matlab/matlab_prog/creating-a-function-handle.html

Answer 2

[Arif Hoq]

x=12:10:42;
out=nonsense(x);

         144         484        1024        1764

function y=nonsense(x)
if mod(x,2) == 0
    y=x.^2;
else
    y=0;
end
disp(y)
end

[meman4567]

Thanks for your answer. That code runs just fine. Now, I am using the following function

function printstuff(func,values)

fprintf('Function evaluated at %d points: \n',length(values))

for q = 1:length(values)

fprintf('point %0.6f has value %0.6f\n',values(q),func(values(q)))

end

end

Then using the two functions I have defined so far (nonsense and printstuff) to run this. This is where it turns me back to 'not enough input arguments'

printstuff(nonsense,[4 11 15 20])

for x = [4 11 15 20]

nonsense(x);

end

[Arif Hoq]

You can do it with a single function.

x = [4 11 15 20];
% x=[4 8 12 16 20];
out=nonsense(x);

Function evaluated at 4 points: 
point 4.000000 has value 16.000000
point 11.000000 has no value 0.000000
point 15.000000 has no value 0.000000
point 20.000000 has value 400.000000

function y=nonsense(x)

fprintf('Function evaluated at %d points: \n',length(x))
for i=1:length(x)
if mod(x(i),2) == 0
    y=x(i).^2;
    fprintf('point %0.6f has value %0.6f\n',x(i),y)
else
    y=0;
    fprintf('point %0.6f has no value %0.6f\n',x(i),y)
end
end

end