write your own version of linspace() with nargin checks in matlab

main.m
function [y] = mylinspace(start, stop, varargin)
% MYLINSPACE generates a row vector of evenly spaced values between two endpoints
%   Y = MYLINSPACE(X1, X2) generates a row vector of 100 evenly spaced
%   points between X1 and X2.
%
%   Y = MYLINSPACE(X1, X2, N) generates N evenly spaced points between X1 and X2.
%
%   Y = MYLINSPACE(X1, X2, N, V) uses V to specify the class of Y. The default
%   value is double. If V is specified, X1 and X2 must be castable to that
%   class.
%
%   The created row vector has N points, inclusive, with X1 and X2 as the
%   first and last points respectively. If N is not specified, the default
%   value is 100. If V is not specified, the default value is double.

n = 100; % Default number of points
classDef = 'double'; % Default class of output

% Check the number of input arguments
switch nargin
    case 2
        % Only start and stop values are given
        N = n;
        classGiven = false;
        
    case 3
        % Start, stop, and number of points are given
        N = varargin{1};
        classGiven = false;
        
    case 4
        % Start, stop, number of points, and output class are given
        N = varargin{1};
        classDef = varargin{2};
        classGiven = true;
        
    otherwise
        % Invalid number of input arguments
        error('Invalid number of input arguments');
end

% Check if the input values are valid
if ~(isnumeric(start) && isscalar(start))
    error('The start value must be a numeric scalar');
    
elseif ~(isnumeric(stop) && isscalar(stop))
    error('The stop value must be a numeric scalar');
    
elseif ~(isnumeric(N) && isscalar(N) && (N == floor(N)) && (N > 0))
    error('The number of points must be a positive integer value');
end

if classGiven
    % Use the specified output class
    y = cast(linspace(start, stop, N), classDef);
else
    % Use the default output class
    y = linspace(start, stop, N);
end

end
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