Iterate over the codes array using a loop, asking for each of the elements if it's equals() to usercode. If one element is equal, you can stop and handle that case. If none of the elements is equal to usercode, then do the appropriate to handle that case. In pseudocode:
found = false
foreach element in array:
if element.equals(usercode):
found = true
break
if found:
print "I found it!"
else:
print "I didn't find it"