Infix to postfix algorithm that takes care of unary operators

Question

The I/p to the algo will be an expression like this:

a+(-b)
a*-b+c

i.e any expression that a standard C compiler would support.

Now

Answer 1

In your input, when you have 2 consecutive operators, the second operator will be unary. If you have more consecutive operators, all but the first will be unary operators.

Transform all your unary - operators to an operand -1 and an operator *, and remove all unary + operators.

If the first element is an operator, it is an unary operator.

Parenthesis are a special case, but you can do a first pass in which you ignore them. In the following example - is consecutive to *.

4*(-(5))

and your tokens would become:

4
*
(
-1
*
(
5
)
)