Variable arguments (varargin, varargout) in MATLAB - Mini Project: Build & Apply

Variable arguments (varargin, varargout) in MATLAB

📖 Scenario: You are creating a MATLAB function that can accept a flexible number of input arguments and return a flexible number of output arguments. This is useful when you want to write a function that can handle different numbers of inputs and outputs without errors.

🎯 Goal: Build a MATLAB function called flexibleSum that uses varargin to accept any number of numeric inputs and returns their sum. Also, use varargout to optionally return the count of inputs and the average of the inputs as additional outputs.

📋 What You'll Learn

Create a function flexibleSum that uses varargin to accept variable inputs

Calculate the sum of all numeric inputs

Use varargout to optionally return the count of inputs and the average

Test the function with different numbers of inputs and outputs

💡 Why This Matters

🌍 Real World

Functions with variable arguments are useful in real-world MATLAB projects where the number of inputs or outputs can change, such as data analysis tools or flexible calculators.

💼 Career

Knowing how to use <code>varargin</code> and <code>varargout</code> is important for MATLAB programmers working in engineering, research, or data science roles where flexible functions improve code reuse and robustness.

1

Create the function header with varargin

Write the first line of the function flexibleSum that accepts variable input arguments using varargin.

MATLAB

% Create the function header with varargin
function total = flexibleSum(varargin)
% Your code here

Need a hint?

Use function keyword and varargin to accept any number of inputs.

2

Calculate the sum of all inputs

Inside the function, create a variable total that sums all numeric values in varargin using a for loop.

MATLAB

function total = flexibleSum(varargin)
% Initialize total
% Your code here

Need a hint?

Start total at 0 and add each input from varargin inside a loop.

3

Add varargout to return count and average

Modify the function header to include varargout. Inside the function, set varargout{1} to the number of inputs and varargout{2} to the average of inputs if requested.

MATLAB

function [total, varargout] = flexibleSum(varargin)
    total = 0;
    for k = 1:length(varargin)
        total = total + varargin{k};
    end
    % Your code here to set varargout

Need a hint?

Use nargout to check how many outputs are requested and assign varargout accordingly.

4

Test the function and display outputs

Call flexibleSum with inputs 10, 20, 30 and capture all three outputs: total, count, and average. Then, use disp to print each output on a separate line.

MATLAB

% Call flexibleSum with 10, 20, 30 and capture outputs
% Your code here

Need a hint?

Use square brackets to capture multiple outputs and disp to show them.