Euler's Method with multiple step sizes

I am currently working on a project for my differential equations class and this is the first part. Most of this was written by my professor, and I cannot find the problem with this code. When I try to run it, I recieve the error shown at the end. Can anyone help me fix this problem?

%%% Define the interval [a,b] and initial condition

a = 0;

b = 0.5;

y0 = 1;

%%% Find the approximated solution using Euler's method

N = 10; %%% number of steps

[x1,y1] = Euler(a,b,y0,N); %%% use the function "Euler" to find the approximate solution with step size h=0.05

N = 100; %%% number of steps

[x2,y2] = Euler(a,b,y0,N); %%% use the function "Euler" to find the approximate solution with step size h=0.005

%%% Define the exact solution

N = 100;

x3 = a:(b-a)/N:b;

y3 = @(x) 2*exp.(x) - x - 1;

%%% Plot the 3 solutions on the same figure

figure;

plot(x1,y1,'r'); hold on;

plot(x2,y2,'g'); hold on;

plot(x3,y3,'b'); hold off;

%%% Euler's method

function [x,y] = Euler(a,b,y0,N)

h = (b-a)/N;

x = a:h:b;

y = zeros(size(x));

f = x+y;

x(1) = a;

y(1) = y0;

%%% main loop for Euler's method

for i = 1:N-1

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

end

end

Unable to perform assignment because the left and right sides have a different number of elements.

Error in Project2_Q1>Euler (line 48)

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

Error in Project2_Q1 (line 16)

[x1,y1] = Euler(a,b,y0,N); %%% use the function "Euler" to find the approximate solution with step size h=0.05

Answer 1

[Torsten]

%%% Define the interval [a,b] and initial condition
a = 0;
b = 0.5;
y0 = 1;
%%% Find the approximated solution using Euler's method
N = 10;                                                     %%% number of steps
[x1,y1] = Euler(a,b,y0,N);                                  %%% use the function "Euler" to find the approximate solution with step size h=0.05
N = 100;                                                    %%% number of steps
[x2,y2] = Euler(a,b,y0,N);                                  %%% use the function "Euler" to find the approximate solution with step size h=0.005
%%% Define the exact solution
N = 100;
x3 = a:(b-a)/N:b;
y3 = 2*exp(x3) - x3 - 1;        
%%% Plot the 3 solutions on the same figure
figure; 
plot(x1,y1,'r'); hold on;
plot(x2,y2,'g'); hold on;
plot(x3,y3,'b'); hold off;
%%% Euler's method
function [x,y] = Euler(a,b,y0,N)
h = (b-a)/N;
x = a:h:b;
y = zeros(size(x));
f = @(x,y)x+y;
y(1) = y0;
%%% main loop for Euler's method
for i = 1:N
    y(i+1) =y(i) + h * f(x(i),y(i));
end
end

[Max]

Thank you so much, you're a life saver