Finds the year that you will be half someone's age.

half_age.py

from datetime import date
from math import floor

def max_ttd(birth_year):
    this_year = date.today().year
    age = this_year - birth_year
    max_year = (100-age) + this_year

    return max_year # agv age is 75, but 100 is safe

def year_to_age(birth_year, cur_year):
    this_year = date.today().year
    age = cur_year - birth_year

    return age

def age_to_year(age): # 65
    this_year = date.today().year

    return this_year - age # 1965

def find_half_age(younger, older):
    this_year = date.today().year


    for year in range(this_year, int(max_ttd(older))):
        dyounger = year_to_age(younger, year)
        dolder = year_to_age(older, year)

        if dyounger == floor(dolder/2):
            return "In year {} you'll be half their age".format(year)

    return "Older would be 100 first."

younger = age_to_year(int(input("How old is the younger person? ")))
older = age_to_year(int(input("How old is the older person? ")))
print(find_half_age(younger,older))