如何为无符号整数类型指定可表示的最大值?
我想知道如何在下面的循环中初始化min，迭代计算一些结构的min和max长度。
var minLen uint = ???
var maxLen uint = 0
for _, thing := range sliceOfThings {
if minLen > thing.n { minLen = thing.n }
if maxLen < thing.n { maxLen = thing.n }
}
if minLen > maxLen {
// If there are no values, clamp min at 0 so that min <= max.
minLen = 0
}
使第一次通过比较，minLen >= n。
当前回答
解决这个问题的一种方法是从值本身获取起始点:
var minLen, maxLen uint
if len(sliceOfThings) > 0 {
minLen = sliceOfThings[0].minLen
maxLen = sliceOfThings[0].maxLen
for _, thing := range sliceOfThings[1:] {
if minLen > thing.minLen { minLen = thing.minLen }
if maxLen < thing.maxLen { maxLen = thing.maxLen }
}
}
其他回答
解决这个问题的一种方法是从值本身获取起始点:
var minLen, maxLen uint
if len(sliceOfThings) > 0 {
minLen = sliceOfThings[0].minLen
maxLen = sliceOfThings[0].maxLen
for _, thing := range sliceOfThings[1:] {
if minLen > thing.minLen { minLen = thing.minLen }
if maxLen < thing.maxLen { maxLen = thing.maxLen }
}
}
来自数学库:https://github.com/golang/go/blob/master/src/math/const.go#L39
package main
import (
"fmt"
"math"
)
func main() {
fmt.Printf("max int64: %d\n", math.MaxInt64)
}
https://golang.org/ref/spec#Numeric_types为物理类型限制。
最大值是在math包中定义的，在你的例子中是math。MaxUint32
注意，因为没有溢出-超过最大值的增量会导致环绕。
一个轻量级包包含了它们(以及其他int类型的限制和一些广泛使用的整数函数):
import (
"fmt"
"<Full URL>/go-imath/ix"
"<Full URL>/go-imath/ux"
)
...
fmt.Println(ix.Minimal) // Output: -2147483648 (32-bit) or -9223372036854775808 (64-bit)
fmt.Println(ix.Maximal) // Output: 2147483647 or 9223372036854775807
fmt.Println(ux.Minimal) // Output: 0
fmt.Println(ux.Maximal) // Output: 4294967295 or 18446744073709551615
我将使用math包来获取整数的最大值和最小值:
package main
import (
"fmt"
"math"
)
func main() {
// integer max
fmt.Printf("max int64 = %+v\n", math.MaxInt64)
fmt.Printf("max int32 = %+v\n", math.MaxInt32)
fmt.Printf("max int16 = %+v\n", math.MaxInt16)
// integer min
fmt.Printf("min int64 = %+v\n", math.MinInt64)
fmt.Printf("min int32 = %+v\n", math.MinInt32)
fmt.Printf("max float64 = %+v\n", math.MaxFloat64)
fmt.Printf("max float32 = %+v\n", math.MaxFloat32)
// etc you can see more int the `math`package
}
输出:
max int64 = 9223372036854775807
max int32 = 2147483647
max int16 = 32767
min int64 = -9223372036854775808
min int32 = -2147483648
max float64 = 1.7976931348623157e+308
max float32 = 3.4028234663852886e+38
