Fixed undefined behavior of tree construction

* Invalid input syntax led to undefined behavior when accessing the top element of an empty stack
** Fixed by introducing a new "topNodeFrom" function which throws an exeption in the case that the given std::stack reference is empty

1 files changed, 1 insertions, 1 deletions

diff --git a/src/parser.h b/src/parser.h
index 54e540a..89c0493 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -6,7 +6,7 @@
 namespace SimpleParser {
 
 double calculate(std::string);
-std::string exportTree(std::string);
+std::string print(std::string);
 
 }