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evan
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 Posted: Sat Jun 28, 2003 5:18 am Post subject: Evaluate such an expression as: (A and B) xor (C or D) |
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Can you give me a hint as how to go about evaluating such an expression. The
actual expression will be different every time (user input). The data will
be sorted in an array or a list.
Thanks,
Evan
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John Harrison
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| Posted: Sat Jun 28, 2003 6:36 am Post subject: Re: Evaluate such an expression as: (A and B) xor (C or D) |
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"evan" <epanagio (AT) frontiernet (DOT) net> wrote
| Quote: | Can you give me a hint as how to go about evaluating such an expression.
The
actual expression will be different every time (user input). The data will
be sorted in an array or a list.
Thanks,
Evan
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You have to write a parser. Best way would be to find an example in a book.
Writing parsers is a big topic in computer science and many books cover this
in more or less depth.
Stroustrup has an example in 'The C++ Programming Language' 3rd edition. His
is an evaluator for arithmetic expressions whereas you seem to have a
logical expression but the principles are just the same.
john
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