Age

There’s been a few occasions now where I have seen developers write code to calculate someone’s age and it has been incorrect.

I was talking to a developer, Alan who was ranting about some incorrect code, so I looked at the review.

string ageInMonths = person.AgeInYears < 6 ? (person.AgeInYears * 12).ToString(): String.Empty,

So there’s an ageInMonths variable. If they are less than 6, then we populate it, otherwise we leave it blank. When we calculate the persons age in months, we simply take their age and multiply it by 12 since there’s 12 months in the year.

Alan begins by pointing out the problem, but Pierre doesn’t understand what he is referring to, so Alan backs it up with more examples…

Alan: Is this correct? If I am 2 months old, I am 2 months old, not 0 month old?

Pierre: yes, it is optional for people less than age of 6

Alan: I don’t think saying someone is 0 months old when they are 11 months is correct. Nor is saying 12 months old when they are 23 months old

Pierre: thanks, will correct it

This isn’t something that is a language barrier. It’s not even a lack of programming experience. It is simply just a lack of common sense. You just have to be human to realise this isn’t how ages work.

He clearly didn’t test it because it should be obvious the correct values weren’t showing. We could instantly see it was a problem just by looking at the code. We didn’t need to see it in action to realise that.