writing an if statement

Hello I am currently trying to write an If statement that will go along a transact of data and end once one of the transacts becomes larger then the first one. Currently i'm trying to write the statement like this.

dunefront = zeros(1,562);
if predune >= postdune
    dunefront = predune;
end

any help would be appreciated. Thanks

Answer 1

[Walter Roberson]

idx = find(transact > transacts(1), 1, 'first');
if isempty(idx)
   ... no transact exceeded the first
else
   ... idx is the index where it exceeded
end