Local and Global Truncation errors for Euler's method

I have coded the following for a Euler's method in Matlab but I am not sure how to incorporate Local and global truncation errors into the code if someone can help.

a = 0;

b = 1;

h = 0.25; % step size

x = a:h:b; % the range of x

y = zeros(size(x)); % allocate the result y

y(1) = 1; % the initial y value

n = numel(y); % the number of y values

% The loop to solve the DE

for i=1:n-1

f = ((x(i)^2)-1)*y(i);

y(i+1) = y(i) + h * f

end

Answer 1

[Torsten]

Just apply the definitions.

Local truncation error at (t_n,y_n):

|y_(n+1) - y(t_(n+1))|

where y(t_(n+1)) is the exact solution to the problem

dy/dt = f(t,y), y(t_n) = y_n

at

t = t_(n+1)

Global truncation error:

|y_num(b) - y(b)|

where y(b) is the value of the exact solution to the problem

dy/dt = f(t,y), y(a) = y0

and y_num(b) is the approximate solution obtained by the numerical method.

Hint: The exact solution to your problem can easily be obtained by separation of variables.