build an array y depending on x

Build an array y by doubling all the elements of a vector x that are positive and adds 10 to all the elements of x that are negative. Note that x could be any length.

Initialise x as indicated above and y to an array of zeroes for the same number as elements as x.

Use a loop to change each element of y as described above. Use the variable i as your loop counter.

[Adam Danz]

What have you tried already to meet these goals?

If you're having trouble getting started, consider going through the Matlab on ramp.

[Mina]

x = input();

for i = 1:x
    if x(i) >= 0
        y = x(i)* 2;
    else
        y = x(i) + 10;
    end   
    disp(y);
end

Answer 1

[the cyclist]

You have a few problems to fix:

As you can see in its documentation, the input function requires you to include some prompting text, such as

input('Enter x: ')

Instead of

for i = 1:x

you want to loop from 1 to the number of elements in x (not from 1 to x itself). You should be able to figure that out. It is not difficult.

Finally, you keep overwriting the same scalar value of y, over and over. Instead, you also want to define a vector y, and only write to each element in turn. Again, I bet you can figure that out (since you are doing something similar with x).