Programming-Idioms

Edit summary for version 15 by programming-idioms.org:
[Go] Variables names and func name

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2017-04-13, 15:25:21

2017-04-13, 15:26:34

Idiom #86 Check if integer multiplication will overflow

Write boolean function multiplyWillOverflow which takes two integers x, y and return true if (x*y) overflows.

Write boolean function multiplyWillOverflow which takes two integers x, y and return true if (x*y) overflows.

func mulOverflows(a, b uint64) bool {
   if a <= 1 || b <= 1 {
     return false
   }
   c := a * b
   return c/b != a
}

func multiplyWillOverflow(x, y uint64) bool {
   if x <= 1 || y <= 1 {
     return false
   }
   d := x * y
   return d/y != x
}

This holds for uint64, not for signed integers.
Note that the multiplication is performed, then its result is checked.

This holds for uint64, not for signed integers.
Note that the multiplication is performed, then its result is checked.

http://grokbase.com/p/gg/golang-nuts/148wvnxk76/go-nuts-re-test-for-an-integer-overflow

http://grokbase.com/p/gg/golang-nuts/148wvnxk76/go-nuts-re-test-for-an-integer-overflow

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