write a functioni = csimpson(f,h) that takes as inputs f an array of function values and h the distance between grid values and computes i the composite simpson’s approximation of the integral in matlab

main.m
function i = csimpson(f,h)
% csimpson calculates the composite simpson's approximation of the integral.
%
% Syntax: i = csimpson(f,h)
%
% Inputs: 
%       f - an array of function values
%       h - the distance between grid values
%
% Outputs:
%       i - the composite Simpson's approximation of the integral.
%
% Example:
%       f = [1 2 3 4 5 6 7 8];
%       h = 1;
%       i = csimpson(f,h); % i = 15
%
% Author: Divyaprakash Mummidi
% Date:   1st September 2021

    n = length(f)-1;
    i = 0;
    
    % If the number of segments is not even
    % then we use the trapezoidal rule for the last segment
    if(mod(n,2) ~= 0)
        i = i + trapezoidal(f(n:n+1), h);
        n = n-1;
    end
    
    % Simpson's rule for the rest of the segments
    for j=1:2:n
        i = i + simpson(f(j:j+2), h);
    end
end

function s = simpson(f,h)
% simpson calculates the simpson's approximation of the integral.
% Simpson's rule is used for every segment except the last one.
%
% Syntax: s = simpson(f,h)
%
% Inputs: 
%       f - an array of function values
%       h - the distance between grid values
%
% Outputs:
%       s - the Simpson's approximation of the integral.
%
% Author: Divyaprakash Mummidi
% Date:   1st September 2021

    s = (h/3) * (f(1) + 4*f(2) + f(3));      
end

function t = trapezoidal(f,h)
% trapezoidal calculates the trapezoidal approximation of the integral.
% Trapezoidal rule is used for the last segment.
%
% Syntax: t = trapezoidal(f,h)
%
% Inputs: 
%       f - an array of function values
%       h - the distance between grid values
%
% Outputs:
%       t - the trapezoidal approximation of the integral.
%
% Author: Divyaprakash Mummidi
% Date:   1st September 2021

    t = (h/2) * (f(1) + f(2));
end
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