in reply to Re^5: Reverse Polish Notation Question
in thread RPN Question

Sorry, I was looking at that because when I've been trying to process long strings I've been getting the error "Modification of non-creatable array value attempted, subscript -2", I fixed it, I needed spaces after everything

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Re^7: Reverse Polish Notation Question
by Anonymous Monk on May 02, 2015 at 03:06 UTC

    That is caused by stack underflow. Add a check for it. For any operator, there must be at least two operands on the stack.

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