Error in using contourf

I got error while running this code which is the error of countourf. How to fix this?

clear, all clc;
x = linspace(-1,1);% create linear spacing in x-direction
y = linspace(-1,1);% create linear spacing in y-direction

%initialise velocity
U = 1;%freestream velocity

%looping in i and j-directions
for i = 1:length(x)
for j = 1:length(y)
    
%create x & y space
xx(i,j) = x(i);
yy(i,j) = y(j);

%calculate radius from x & y
rad(i,j) = sqrt(x(i)^2 + y(j)^2);

% calculate angle from x and y
if x(i) > 0
theta(i,j) = atan(y(j)/x(i));

elseif x(i) <0 && y(j) >= 0
theta(i,j) =atan(y(j)/x(i))+pi;

elseif x(i) < 0 && y(j) < 0
theta(i,j) = atan(y(j)/x(i))-pi;

elseif x(i) == 0 && y(j) < 0
theta(i,j) = pi/2;

else
theta(i,j) = -pi/2;
end

% calculate stream function using polar coordinate system
psi(i,j) = U *rad(i,j)*sin(theta(i,j));
% calculate velocity potential using polar coordinate system
phi(i,j) = U*rad(i,j)*cos(theta(i,j));
end
end
%plotting
contourf(xx,yy,psi,-1:0.2:1,'k','LineWidth',1.5), hold on�% plot stream function for range -1:0.1:1
contour(xx,yy,phi,-1:0.2:1,'r','LineWidth',1.5)% plot velocity potential for range -1:0.2:1
axis image, hold off
legend('streamlines','potential')
title('Uniform stream in x-direction')
xlabel('x-coordinate'), ylabel('y-coordinate')
axis square;
% end of Octave program

Answer 1

[Star Strider]

There is an invalid text character:

contourf(xx,yy,psi,-1:0.2:1,'k','LineWidth',1.5), hold on�% plot stream function for range -1:0.1:1
                                                         ↑ ← HERE

If that is corrected (eliminated), your code appears to work (in MATLAB R2020b Update 3).

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