- Back in
recur(3) - Finished the recurusive call, got back
"1" - Computes
"0" + "1", which is"01" - Stops and returns
"01"
Resulting call stack
r(1) returns "1"
r(3) dig -> "0" "0" + "1" returns "01"
r(10) dig -> "1" "1" + ____
r(32) dig -> "2" "2" + ____