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Not enough input arguments

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Serena Simpson
Serena Simpson on 13 Oct 2020
Edited: Stephen on 13 Oct 2020
Hi, I wrote a function that needs to accept user input and then call the function ussing that input. However, it says not enough input arguments.
%% Section 1: Initalization of Variables
%[r, h] = cylind(r, h);%Intializing the varibles
r = input('What is the r?');
h = input('What is the h?');
%% Section 2: Result Output
fprintf("v is %d, sa is %d\n", cylind)
%% Section 3: Processing
cylind(r, h)
function [r, h] = cylind(r, h) %function for surface area and volume
v = pi*(r^2)*h;
sa = (2*pi*(r^2)) + (2*pi*r*h);
end

Answers (2)

Bandar
Bandar on 13 Oct 2020
Edited: Bandar on 13 Oct 2020
You are defining the names of inputs like the names of the ouputs. The proper header of function is like this
function [outputs] = <function_name>(inputs)

Stephen
Stephen on 13 Oct 2020
Edited: Stephen on 13 Oct 2020
There are two main bugs that we need to fix:
  1. define the correct function outputs.
  2. call the function with input and output arguments.
Lets have a look at them in detail.
1- Currently you define the function with exactly the same input and output arguments:
function [r, h] = cylind(r, h)
While this is perfectly valid and useful in some situations, in your case you want to return the values of the internal calculations, i.e. the variables v and sa, so these need to be defined as the output arguments, e.g. like this:
function [v, sa] = cylind(r, h)
2- You call the cylind function twice, but the first time with no input arguments (even though it requires two input arguments) and the secdon time with no output arguments. Calling a function with no output arguments is perfectly valid, but it just means that any outputs it calculates internally are simply discarded. If you want to use the outputs then you need to assign then to some variables, e.g.:
[Vout,SAout] = cylind(..)
Note that the names used internally are totally unrelated to the names used in the calling workspace!
So we can call the fixed function:
function [v,sa] = cylind(r,h)
v = pi*(r.^2).*h;
sa = (2*pi*(r.^2))+(2*pi*r.*h);
end
simply like this:
>> Rin = 2;
>> Hin = 3;
>> [Vout,SAout] = cylind(Rin,Hin)
Vout = 37.699
SAout = 62.832
̀>> fprintf("v is %g, sa is %g\n", Vout,SAout) % changed to %g
v is 37.6991, sa is 62.8319

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