向上取整

package main

import(
	"fmt"
	"math"
)

func main() {
	a := 123.23
	b := math.Ceil(a)
	fmt.Println(b)
}
输出：124

向下取整

package main

import(
	"fmt"
	"math"
)

func main() {
	a := 123.23
	b := math.Floor(a)
	fmt.Println(b)
}
输出：123