In the Snippets to Go article "LeapYear Function Might Have You Leaping for Joy" (February 2006, InstantDoc ID 48663), Jim Turner created the LeapYear function to determine whether a specified year is a leap year. As Listing 1 shows, I also created a function called IsLeapYear to determine leap years.
The IsLeapYear function is based on information provided by Bo Eschricht in "A More Elegant Approach for Determining Leap Years" (Scripting Central, http://www.windowsitpro.com/windows/article/articleid/
49046/49046.html). As Bo pointed out, you can determine a leap year by dividing the year by 400 if it's a centennial year (e.g., 2000, 3000) or by 4 if it's a noncentennial year (e.g., 2007, 2008). If the year divides evenly (i.e., no remainder), it's a leap year. Otherwise, it's a nonleap year.
Listing 2 demonstrates how you can use the IsLeapYear function in a script. You simply use the intYear variable to pass in the year you want to test, as callout A in Listing 2 shows. When you run the script, a message box appears telling you whether or not that year is a leap year.
—Olli Krollmann