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51 $ scala -cp postfix.jar |
51 $ scala -cp postfix.jar |
52 |
52 |
53 scala> CW8a.syard(CW8a.split("( 5 + 7 ) * 2")) |
53 scala> CW8a.syard(CW8a.split("( 5 + 7 ) * 2")) |
54 val res0: CW8a.Toks = List(5, 7, +, 2, *) |
54 val res0: CW8a.Toks = List(5, 7, +, 2, *) |
55 \end{lstlisting}%$ |
55 \end{lstlisting}%$ |
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56 |
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57 |
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58 \subsection*{Hints} |
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59 |
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60 \noindent |
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61 \textbf{For the Preliminary Part:} useful operations for determining |
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62 whether a string is a number are \texttt{.forall} and \texttt{.isDigit}. |
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63 One way to calculate the the power operation is to use \texttt{.pow} |
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64 on \texttt{BigInt}s, like \texttt{BigInt(n).pow(m).toInt}. |
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65 \bigskip |
56 |
66 |
57 |
67 |
58 \subsection*{Preliminary Part (3 Marks, files postfix.scala, postfix2.scala)} |
68 \subsection*{Preliminary Part (3 Marks, files postfix.scala, postfix2.scala)} |
59 |
69 |
60 The \emph{Shunting Yard Algorithm} has been developed by Edsger Dijkstra, |
70 The \emph{Shunting Yard Algorithm} has been developed by Edsger Dijkstra, |