Implementing Nearest neighbor heuristics in Matlab

Nearest-neighbor heuristics (go to the nearest unvisited city). Write an algorithm in which chooses the next city in the path to be the closest city that have not already visited. Once all cities have been visited, the salesman return home.

Hint: Use the matlab codes provided below to perform this task.

I am not getting accurate result, it shows error. Can someone kindly check my code and fix it?? Thanks in advance. :)

% This is a script which I wrote to encapsulate the state capital location data %
clear
close all

function City = Capitals()
% Creates a length 48 structure array where each component
% has three fields:
%    Name   a length 24 string with the state and capital city's name
%    Lat    latitude in degress
%    Long   longitude in degrees
A = [...
      'AL  Montgomery          32.38     86.37';...
      'AZ  Phoenix             33.43    112.22';...
      'AR  Little Rock         34.73     92.23';...
      'CA  Sacramento          38.52    121.50';...
      'CO  Denver              39.75    104.87';...
      'CT  Hartford            41.78     72.78';...
      'DE  Dover               39.17     75.53';...
      'FL  Tallahassee         30.38     84.37';...
      'GA  Atlanta             33.75     84.38';...
      'ID  Boise               43.57    116.22';...
      'IL  Springfield         39.83     89.67';...
      'IN  Indianapolis        39.73     86.28';...
      'IA  Des Moines          41.53     93.65';...
      'KS  Topeka              39.77     95.63';...
      'KY  Frankfurt           38.20     84.88';...
      'LA  Baton Rouge         30.53     91.15';...
      'ME  Augusta             44.30     69.77';...
      'MA  Boston              42.37     71.33';...
      'MD  Annapolis           38.97     76.49';...
      'MI  Lansing             42.78     84.60';...
      'MN  St.Paul             44.88     93.22';...
      'MS  Jackson             32.32     90.88';...
      'MO  Jefferson City      38.57     92.18';...
      'MT  Helena              46.60    112.00';...
      'NE  Lincoln             40.85     96.75';...
      'NV  Carson City         39.17    119.77';...
      'NH  Concord             43.20     71.50';...
      'NJ  Trenton             40.22     74.77';...
      'NM  Santa Fe            35.62    106.88';...
      'NY  Albany              42.75     73.80';...
      'NC  Raleigh             35.87     78.78';...
      'ND  Bismarck            46.77    100.75';...
      'OH  Columbus            40.00     82.88';...
      'OK  Oklahoma City       35.40     97.60';...
      'OR  Salem               44.92    123.33';...
      'PA  Harrisburg          40.20     76.77';...
      'RI  Providence          41.73     71.43';...
      'SC  Columbia            34.00     81.55';...
      'SD  Pierre              44.38    100.28';...
      'TN  Knoxville           35.82     83.98';...
      'TX  Austin              30.30     97.70';...
      'UT  Salt Lake City      40.77    111.97';...
      'VT  Montpelier          44.25     72.58';...
      'VA  Richmond            37.50     77.33';...
      'WA  Olympia             46.97    122.90';...
      'WI  Madison             43.77     89.40';...
      'WV  Charleston          38.37     81.60';...
      'WY  Cheyenne            41.15    104.80'];
      
for k=1:48
    Lat  = str2num(A(k,25:29));
    Long = str2num(A(k,34:39));
    City(k) = struct('Name',A(k,1:24),'Lat',Lat,'Long',Long);
end
end

% 2nd script: This will compute the great circle distance between the two cities given their respective lattitudes and longitudes %

function d = Dist(C1,C2)
% Great circle distance between city C1 and city C2.
theta1 = C1.Lat*pi/180; 
phi1 = C1.Long*pi/180;
theta2 = C2.Lat*pi/180; 
phi2 = C2.Long*pi/180;
xDiff = cos(theta1)*cos(phi1) - cos(theta2)*cos(phi2);
yDiff = cos(theta1)*sin(phi1) - cos(theta2)*sin(phi2);
zDiff = sin(theta1) - sin(theta2);
d = 7926*asin(sqrt(xDiff^2 + yDiff^2 + zDiff^2)/2);

% 3rd script: This will set up the distance matrix given a set of input cities and their locations %

function D = CityDistTable(City)
% City is a length n structure array where the name, latitude, and
% longitude of the kth city is housed in City(k).Name, City(k).Lat,
% and City(k).Long.
% D is an n-by-n matrix with D(i,j) being the great circle distance
% from City(i) to City(j).

% Set up the city-to-city distance matrix...
n = length(City);
D = zeros(n,n);
for i=1:n
    for j=i+1:n
        D(i,j) = Dist(City(i),City(j));
        D(j,i) = D(i,j);
    end
end

% 4th script: This script is going to create a route from city i to city j %

function [S,Odom] = Route(StartCity,D)
% D is an n-by-n matrix whose (i,j) entry is the distance
%    between city i and city j.
% StartCity is an index with 1 <= StartCity <= n
% S and Odom are column vectors of length n+1.  S(k) is the index of
% the kth stop and Odom(k) is the accumulated mileage at that point.
% Note that S(1) = StartCity , Odom(1) = 0, S(n+1) = StartCity, and
% S(n+1) is the total distance of the journey.
[n] = size(D);
% Get set at the starting city...
S     = zeros(n+1,1);
Odom  = zeros(n+1,1);
Here  = StartCity;
S(1) = Here;
% Remember the distance to the starting city...
dStart = D(StartCity,:);
for j=1:n-1
    % Figure out where to go next, i.e., stop j+1...
    D(:,Here) = inf;
    [Leg,Next]  = min(D(Here,:));
    % Update the odometer and move on...
    Odom(j+1)  = Odom(j) + Leg;
    S(j+1) = Next;
    Here = Next;
end
% Return to the starting city...
S(n+1) = StartCity;
Odom(n+1) = Odom(n) + dStart(Here);


% 5th and last script: This route applies 48 times to calculate the heuristic solution of TSP %

% Script Eg15_1
% Heuristic solution of the traveling salesperson problem.

clc
close all
% Get the data and set up the distance matrix...
City = Capitals();
D = CityDistTable(City);

Shortest = inf;
% Examine the route obtained for each possible starting city...
for StartCity = 1:48
    [S,Odom] = Route(StartCity,D);
    if Odom(49) < Shortest
        % A new best route discovered. Display...
        Shortest = Odom(49);
        clc
        disp('       Stop              Odometer')
        disp('---------------------------------')
        for k=1:49
            disp([City(S(k)).Name  sprintf(' %6.0f',Odom(k)) ])
        end
        pause
    end
end

% End of all scripts % 

[Purva Joshi]

It should be used three ends at the end of the code.