my Plot not showing a line only the points

I need to show the plot with continous line but it keep plotting only the points, I don't understand the reason .

% Numerical Method of Solving ODE \ Euler Method%

'Example (1)''dy/dx=-y'

dy = @(x,y)-y;

f = @(x)exp(-x);

x0 = 0;

xn = 1;

y = 1;

h = 0.1;

fprintf (' x \t\t y (Euler)\t y(Exact) \n') % data table header

for x = x0 : h : xn-h

y = y + dy(x,y)*h;

x = x + h;

hold on

plot(x,y,'or');

xlabel('X');

ylabel('Y-by Euler method');

hold on

y2 = f(x);

plot(x,y2,'ob')

hold off

fprintf ('%f \t %f\t %f\n',x,y,f(x));

end

Answer 1

[Walter Roberson]

At any one time your x and y are scalar. plot() only produces lines when there are at least two adjacent finite points in a single plot call.

You should store all the x and y values and do the plot all at once afterwards.

[Mustafa Abdalla Zakiedin]

Thank you Mr.Roberson for your response, It make sense now

Answer 2

[Bhaskar R]

If you need plot as line in anyway take additional variables to plot it

% Numerical Method of Solving ODE \ Euler Method%
% 'Example (1)''dy/dx=-y'
dy = @(x,y)-y;
f = @(x)exp(-x);
x0 = 0;
xn = 1;
y = 1;
h = 0.1;
fprintf (' x  \t\t  y (Euler)\t   y(Exact) \n') % data table header
% initialize dummy of the x, y, y2 as dummy so that you can plot outside
dummy_x = zeros(1, length(x0 : h : xn-h));
dummy_y = zeros(1, length(x0 : h : xn-h));
dummy_y2 = zeros(1, length(x0 : h : xn-h));
k = 1; % counter variable
for x = x0 : h : xn-h
    y = y + dy(x,y)*h;
    x = x + h;
    dummy_y(k) = y;
    dummy_x(k) = x;
    y2 = f(x);
    dummy_y2(k) = y2;
    fprintf ('%f \t %f\t %f\n',x,y,f(x));
    k = k+1;    
end
figure, hold on
plot(dummy_x,dummy_y,'-o');
xlabel('X');
ylabel('Y-by Euler method');
hold on
plot(dummy_x, dummy_y2,'-o')
hold off

[Mustafa Abdalla Zakiedin]

All thanks dear Bhaskar R, Its worked fine now