问题及解答

>> a=-1.2
----------------------------
 type: double
 name: a
value: -1.2
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>> a
in> -1.2

out> -1.2
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>> -a
in> --1.2
hint> ===*=== syntax error ===*===
         > It is not a valid expression.
         > type `:help` to view some rules.

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>> -1*a
in> -1*-1.2
hint> ===*=== syntax error ===*===
         > It is not a valid expression.
         > type `:help` to view some rules.

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>> -1*(a)
in> -1*(-1.2)

out> 1.2
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>> a*(-1)
in> -1.2*(-1)

out> 1.2
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