Function arguments in MATLAB are essential components that allow data to be passed into and out of functions. They enable flexible and reusable code by parameterizing function behavior.

Input Arguments

Input arguments are variables that a function receives when it is called. They provide the necessary data for the function to perform its operations.

Syntax

function [output1, output2] = functionName(input1, input2, input3)
    % Function body
end

In this syntax, input1, input2, and input3 are the input arguments.

Example

function result = addNumbers(a, b)
    result = a + b;
end

sum = addNumbers(5, 3);  % sum will be 8

Output Arguments

Output arguments are the values that a function returns after execution. They allow functions to provide results back to the calling code.

Multiple Outputs

MATLAB functions can return multiple output arguments, which is particularly useful for complex operations.

function [sum, difference] = mathOperations(a, b)
    sum = a + b;
    difference = a - b;
end

[s, d] = mathOperations(10, 7);  % s will be 17, d will be 3

Optional Arguments

MATLAB allows for optional function arguments, providing default values when an argument is not specified.

function result = powerOf(base, exponent)
    if nargin < 2
        exponent = 2;  % Default exponent is 2 if not provided
    end
    result = base ^ exponent;
end

square = powerOf(5);      % Returns 25 (5^2)
cube = powerOf(5, 3);     % Returns 125 (5^3)

The nargin function is used to check the number of input arguments provided.

Variable Number of Arguments

For functions that need to handle a varying number of inputs, MATLAB provides the varargin cell array.

function result = sumAll(varargin)
    result = sum([varargin{:}]);
end

total = sumAll(1, 2, 3, 4, 5);  % Returns 15

Best Practices

Use meaningful names for function arguments to improve code readability.
Document the expected input types and sizes in the function comments.
Validate input arguments at the beginning of the function to ensure proper usage.
Consider using inputParser for complex input validation in larger functions.
Limit the number of input arguments to maintain function simplicity and usability.

Related Concepts

To further enhance your understanding of MATLAB functions and their arguments, explore these related topics:

Mastering function arguments in MATLAB is crucial for writing efficient, reusable, and maintainable code. Practice creating functions with various argument configurations to solidify your understanding.