How to write coding for the following problem

How to calculate the following loop

y(1)=x;
for i=1:3
y(i+1)=z(i)+y(i);
i=i+1;
end

Ans=z(1)+z(2)+z(3)+3*x

[Kevin Claytor]

You don't need the "i=i+1" statement - the increment is contained next to the for statement;

for i = start:increment:end
  disp(i);
  i = i+1;
end

So for start = 1, increment = 1, end = 3 you would get "1 2 3" For start = 2, increment = 2, end = 7 you would get "2 4 6" Your added "i=i+1" affects everything after it, but then the value for i is re-written when the for loop begins again. For example, try this;

for i = 1:3
  disp(i);
  i = i+1;
  disp(i)
end

Should give you the output; "1 2 2 3 3 4"

Answer 1

[Luffy]

 Assuming z is a vector of length 3,x is scalar
 y = zeros(1,4)
 y(1)= x;
 for i = 1:3
 y(i+1) = y(i)+z(i);
 end
 y(4) + 2*x  % How did you get 3*x,do you want y(4)/ans you specified

Answer 2

[F.]

Hello, I don't understand how you can make i=i+1 in a loop on i !! ;-)

When I see your code, I can write this:

   y(1) = x
   y(2) = z(1) + y(1) = z(1) + x
   y(3) = z(2) + y(2) = z(1) + z(2) + x
   y(4) = z(3) + y(3) = z(1) + z(2) + z(3) + x

so:

   y(n+1) = sum( z(1:n) ) + x

and not what you wrote:

   Ans=z(1)+z(2)+z(3)+3*x

Where is the problem ....