Python code
''' Parse and execute an expression like: ("3 +(5*(4/2)3-2)+(1+2)(6-4)+( 5)")
Target: Understand python normal programming, Class, list, Stack (last in, first out) Depth first and width first way to iterate a tree A subset of express Parse and Execute
Run in: Phthon 2.7.x Not Run in: Python 3.x (due to the change of "print"), quick change could make it run again
Dependency: All buildin modules
Support: +, -, *, /, (, ), int(>=0) Not support: hex(0x...), negitave int( like -3) '''