golang float64，in64相互转换精度控制

//将float64转成精确的int64
func Wrap(num float64, retain int) int64 {
	return int64(num * math.Pow10(retain))
}

//将int64恢复成正常的float64
func Unwrap(num int64, retain int) float64 {
	return float64(num) / math.Pow10(retain)
}
//精准float64
func WrapToFloat64(num float64, retain int) float64 {
	return num * math.Pow10(retain)
}
//精准int64
func UnwrapToInt64(num int64, retain int) int64 {
	return int64(Unwrap(num, retain))
}