You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: transectc.m
    path of file: ./repos/CDT/cdt
    
    the code of the file until where you have to start completion: function [C,h] = transectc(x,d,v,varargin)
% transectc produces a contour plot oceanographic data from CTD profiles 
% collected at different locations and/or times.  
% 
%% Syntax 
% 
%  transectc(x,d,v)
%  transectc(...,levels)

    
function [C,h] = transectc(x,d,v,varargin)
% transectc produces a contour plot oceanographic data from CTD profiles 
% collected at different locations and/or times.  
% 
%% Syntax 
% 
%  transectc(x,d,v)
%  transectc(...,levels)
%  transectc(...,LineSpec)
%  transectc(...,'Name',Value)
%  transectc(...,'extrap')
%  transectc(...,'interp','InterpMethod)
%  transectc(...,'di',di)
%  transectc(...,'xi',xi)
%  [C,h] = transectc(...)
% 
%% Description 
% 
% transectc(x,d,v) creates a contour plot diagram of the variable v
% at the horizontal locations (or times) x and depths d. x must be a numeric
% array of values indicating the locations or times of each CTD profile. Inputs
% d and v must each be cell arrays containing depths and measurements at each
% CTD location. 
%
% transectc(...,levels) specifies the values of v to draw as contour lines. 
% If levels is a scalar value, then transectc draws that number of contour 
% lines. If levels is an array, a contour line is plotted for each value in 
% levels. To draw the contours at one value (k), specify levels as a two-element
% row vector [k k].
%
% transectc(...,LineSpec) specifies the style and color of the contour lines.
% 
% transectc(...,'Name',Value) specifies additional options for the contour plot
% using one or more name-value pair arguments. Specify the options after all other 
% input arguments. For a list of properties, see Contour Properties.
% 
% transectc(...,'extrap') turns on the option to extrapolate beyond the extents
% of data. By default, transectc does not extrapolate, but the option is available
% to fill in gaps, such as between lowest datapoint and the seabed. 
% 
% transectc(...,'interp','InterpMethod) specifies an interpolation method 
% used for the contouring. Default is 'linear'.
% 
% transectc(...,'di',di) specifies interpolation depths di. By default, transectc
% creates a grid by interpolating to 1000 equally-spaced depths between the 
% shallowest and deepest measurement. 
% 
% transectc(...,'xi',xi) specifies interpolation locations (or times) xi. By 
% default, transectc interpolates to 2000 equally-spaced points xi between the 
% minimum and maximum values of x.  
% 
% [C,h] = transectc(...) returns the contour matrix C and the handle h
% of the plotted objects.
% 
%% Methods
% This function grids unevenly spaced data by the method described in the 
% documentation for the transect function, then plots the gridded data with 
% Matlab's built-in contour function. 
% 
%% Examples: 
% For examples, type 
% 
%  cdt transectc
% 
%% Author info
% This function and supporting documentation were written by Chad A. Greene
% of the University of Texas at Austin, 2018. 
% 
% See also: contour and transect.

%% Initial error checks: 

narginchk(3,Inf) 
assert(isnumeric(x),'Error: x must be a numeric array.') 
assert(iscell(d),'Error: d must be a cell array.') 
assert(iscell(v),'Error: v must be a cell array.') 
assert(isequal(numel(x),numel(d),numel(v)),'Dimensions of x, d, and v must all agree.') 

%% Set defaults: 

InterpMethod = 'linear'; 
extrap = false; % interpolation extrapolation method
userdi = false; % user-defined di
userxi = false; % user-defined xi

%% Parse Inputs: 


% Interpolation method: 
tmp = strncmpi(varargin,'interpolation',6); 
if any(tmp)
   InterpMethod = varargin{find(tmp)+1}; 
   tmp(find(tmp)+1) = true; 
   varargin = varargin(~tmp); % discards this name-value pair
end