The constants and operators of the Go language

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Constants and operators

2. You must assign a value after a constant declaration, and in a constant declaration group, the value can be an upward principle
   Example:
   Const (
   AA1 = 1
   Bb1
   Cc1
   )
   BB1 and CC1 are not assigned, then BB1 follows the upward principle, the value equals Aa1, and then cc1 follows the upward principle, cc1 equals the value of BB1, so that three constants have values.

4. Enumeration Iota
   Const (
   Aa1 = Iota
   Bb1
   Cc1
   )
   When a constant group uses the Iota enumeration, the member values start from 0 to increment. That means aa1= 0,bb1=1, so what's the bottom?

   Const (
   Cas
   BB1 = Iota
   Cc1
   )
   The result is the same, as long as the iota is used within the group, wherever it is, it is incremented from the first constant of the group.
   It will reset if it encounters a const, for example:
   Const (
   Cas
   BB1 = Iota
   CC1 = Iota
   )
   Const (
   Aa2 = Iota
   Bb2
   Cc2
   )
   There is only one iota in the same group, even if more than one is written,
   Encountered const, equivalent to bounds, iota range only within one const range

6. Small exercise: Using iota, and constants, and << operators to implement computer units: B,KB,MB,GB representation

   const (B float64 = 1 << (iota * 10)KBMB)定义为float是怕数据溢出，利用iota的自增长以及const组省略值后，后一个值跟随前一个值一样，这里是计算表达式的跟随，因为其中iota变化了，所以在计算时就变化了。实现了要求。

8. Operator:

   一元：^:数据加一取反，无论正负数。     ！：取非二元：^：异或     &：与运算     |：或运算     &^：同样是位运算，第二个数的位如果是1，那么把第一 个数的对应位改为0，如果不是1，那么不变，这样结果是第一个数运算之后的结果。