Take the InfixSum codes from InfixSum.jar.
The provided TokenIterator is ***VERY PRIMITIVE***. It does not read tokens as defined in the programming assignments. It only reads one character tokens. Extend the code in ParseTreeExpr so that it parses full arithmetic expressions:
expr = term ( "+"|"-" term )* term = factor ( "*"|"/" factor )* factor = "-" factor | number | "(" expr ")"
You can use your own token iterator or the primitive one provided.