Merge pull request #11 from Xieyan/master

function declaration
Merge pull request #12 from Xieyan/master

error 15 need fixing
error type 15 fixed
all test well
finished
intercode datastructure
Exp Cond added
Exp Cond added
first test successful
first test successful
Merge pull request #5 from stanleytangerror/master

first testcode successful