how to use for loop?

i want to know how to perform calculations on a vector with both positive and negative numbers,

I have this vector x=[2 -5 6 7 -4 8 -5 6]

im told to use a loop to double the positive numbers but i dont know how to

extract the negative numbers and perform calculations using the for loop

what am i supposed to do?

[madhan ravi]

doc for

Answer 1

[Image Analyst]

In the for loop, use an if. Here's a start.

for ......
     if x(.....) > 0
        % If it's positive
        % x(...... = 2 * .................. % Multiply by 2         
     end
end