datediff.py

# cf. book 7.7 exercises 11-13

def yearLength(year):
    if year % 400 == 0:
        return 366
    elif year % 100 == 0:
        return 365
    elif year % 4 == 0:
        return 366
    else:
        return 365

def monthLength(year,month):
    if month == 2 and yearLength(year) == 366:
        return 29
    elif month == 2:
        return 28
    elif month in [4,6,9,11]:
        return 30
    else:
        return 31

def dateDays(year,month,day):
    days = 0
    for y in range(year):
        days = days + yearLength(y)
    for m in range(1,month):
        days = days + monthLength(year,m)
    return days + day

def dateDiff(year1,month1,day1,year2,month2,day2):
    diff = dateDays(year2,month2,day2) - dateDays(year1,month1,day1)
    return diff

#### new stuff added for Lecture 6

def checkDate(year,month,day):
    return (0 < month <= 12) and (0 < day <= monthLength(year,month))

def inputDate(prompt):
    date = (input(prompt + ", format år,månad,dag: ")).split(',')
    if len(date) == 3 and date[0].isdigit() and date[1].isdigit() and date[2].isdigit():
        year,month,day = int(date[0]),int(date[1]),int(date[2])
        if checkDate(year,month,day):
            return year,month,day
        else:
            print("ogiltigt datum")
            return inputDate(prompt)
    else:
        print("försök igen, tre tal")
        return inputDate(prompt)
    
#### end new stuff

### old versions step by step, not used in the actual main()
def inputDate1(date):
    year,month,day = eval(input("Ange " + date + " i format år,månad,dag: "))
    return year,month,day

def inputDate2(prompt):
    year,month,day = input(prompt+": ").split(',')
    return int(year),int(month),int(day)

def inputDate3(prompt):
    date = (input(prompt + ": ")).split(',')
    if len(date) == 3:
        return int(date[0]),int(date[1]),int(date[2])
    else:
        print("ogiltigt datum")
        return inputDate3(prompt)

def inputDate4(prompt):
    date = (input(prompt + ": ")).split(',')
    if (len(date) == 3
            and date[0].isdigit()
            and date[1].isdigit()
            and date[2].isdigit()):
        return int(date[0]),int(date[1]),int(date[2])
    else:
        print("ogiltigt datum")
        return inputDate4(prompt)
##########

    
def main():
    try:
        year1,month1,day1 = inputDate("startdatum")
        year2,month2,day2 = inputDate("slutdatum")
        print("Skillnaden är", dateDiff(year1,month1,day1,year2,month2,day2))
    except KeyboardInterrupt:
        print()
        print("om du vill lämna programmet, tryck ^D")
        main()
    except:
        print()
        print("Ok, hejdå")

if __name__ == '__main__':
    main()