how can I rewire these codes in a different way.

% boundary conditions and point forces

for i = 1:size(node,1)

if node(i,2)^2+node(i,3)^2 < 4.01^2

flags(node(i,1)) = 2; % flag nbc as 2

e_bc = [e_bc; node(i,1)];

e_bc(i) = 20;

end

end

%coords of essential B.C.

nd = size(e_bc,1); % number of nodes on essential boundary

% nd = 9; % number of nodes on essential boundary

%

% % essential B.C.

% flags(1:5) = 2; e_bc(1:5) = 0.0;

% flags(6:5:21) = 2; e_bc(6:5:21) = 0.0;

% plots

compute_flux = 'yes';

plot_mesh = 'yes';

plot_nod = 'yes';

plot_temp = 'yes';

plot_flux = 'yes';

% natural B.C - defined on edges positioned on natural boundary

% essential B.C.

n_bc = [];

for i = 1:size(node,1)

if node(i,2)^2+node(i,3)^2 > 4.199^2 && node(i,3)>0

a=(-1380)*sin(atan(node(i,3)/node(i,2)));

n_bc = [n_bc; [i,a]];

end

end

n_bc_d = sortrows(n_bc,2);

% arrange element in descending order based on q

n_bc = [];

for i = 1:size(n_bc_d,1)-1

b=[n_bc_d(i,1);n_bc_d(i+1,1);n_bc_d(i,2);n_bc_d(i+1,2)];

n_bc = [n_bc,b];

end

n_bc ;

nbe = size(n_bc,2); % natural B.C.