Go 如何获取三个月前的月份日

这是我写的关于日期的包，有获取前一天的函数，你看看有没有帮助。 package xinxi import ( "strconv" "time" ) //日期类型 type Date struct { Year int Month int Day int Week int } var ( daycount = [12]int{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31} weekday = []rune("日一二三四五六") ) //日期字符串方法 func (date *Date) String() string { y, m, d := strconv.Itoa(date.Year), strconv.Itoa(date.Month), strconv.Itoa(date.Day) if date.Month < 10 { m = "0" + m } if date.Day < 10 { d = "0" + d } s := y + "-" + m + "-" + d return s } //星期字符串方法 func (date *Date) WeekString() string { return "星期" + string(weekday[date.Week]) } //前一天 func (date *Date) Prev() Date { var front Date if date.Day == 1 { if date.Month == 1 { front.Day = daycount[11] front.Month = 12 front.Year = date.Year - 1 } else { if date.Month == 3 { if LeapYear(date.Year) { front.Day = daycount[1] + 1 } else { front.Day = daycount[1] } front.Month = 2 front.Year = date.Year } else { front.Day = daycount[date.Month-2] front.Month = date.Month - 1 front.Year = date.Year } } } else { front.Day = date.Day - 1 front.Month = date.Month front.Year = date.Year } if date.Week == 0 { front.Week = 6 } else { front.Week = date.Week - 1 } return front } //获取当前日期 func DateNow() Date { dateN := Date{} now := time.Now() dateN.Year = now.Year() dateN.Month = int(now.Month()) dateN.Day = now.Day() dateN.Week = int(now.Weekday()) return dateN } //测试闰年 func LeapYear(year int) bool { if year%4 == 0 { return true } return false }