Loop and numeric comparison

Hello

i want to compare a value with the last n values and see if its the highest than the last n. I have tried to do a function like this

function varargout = close(Price, NumberofDays)

for j = NumberofDays : NumberofDays : size(Price)
    for i = 1:size(Price)
        if i ~= j

          if Price(j) > Price(j-i) 
              msgbox('ok')
          else
              msgbox('ko')
          end 

          else

              break

          end

      end

      end

      end

The comparison is not coded yet, I am just making sure its targeting the right values. but unfortunately I am having an issue when it goes out of the inside loop and increment for the first time. For example

let say i want to compare Value 5 with the last 5 values

j will be equal to 5 then i will be incrementing on i, which will go from 1 to 4 when its 5, it will quit the loop and increment for the first time for j, but on the second, I will want Value 10(j) to be compared to Value 5, then 6,7,8,9, but its re starting from 1. I know my code is written to do this but I cant find a way to make it after each j loop to start from the last j of the previous loop. I dont know if i am clear .

Thank you very much

D