I need help creating a function for taking an array and reversing it and i have to use a for loop. I have looked online but i really dont know what i am doing?

function result = reverse_array(array)
 result = array;
  for(index = zero(1,length(array)))
     index =  reverse_array(index) = array(length(array)-index+1);
  end
end

[nick sorge]

it needs take an array from a random walk function and reverse it.

Answer 1

[Evan]

There are built-in functions for this, such as fliplr and rot90.

However, if you want to use a loop, think about the process you want to do, step-by-step. You want to create a new array that is a flipped version of an array you send into the function. So you want to access each element of the array in reverse, from end to beginning, and assign it to your new array, from beginning to end.

function y = flip_array(x)

     n = ?
     x_indices = ?

     for y_index = 1 : n

        x_index = x_indices(y_index);
        y(y_index) = x(x_index);

     end

end

You just need to find a a value n that tells you how long your new array is going to be, then an array of x indices that gives you want you want. Think about how the colon ( : ) operator can be used, and remember that you can use it to create arrays that count up or down.

[nick sorge]

I need to use a for loop the arrays need to be the same length. There isn't a set value it needs to able to take numbers from a random walk function and reverse them.

[nick sorge]

so for n would i just put in the random walk function that i already created or how would i do that if the random walk array can change size?

[Evan]

n tells you how many iterations the loop goes through. You need to pass over each element in your array, however long it is. So n isn't the array itself, but information about that array. You need some function (a builtin matlab function) that will get you this information.