import java.time.LocalDate
fun main() {
// Define the variables as requested
val startdate: LocalDate = LocalDate.of(2026, 1, 15)
val enddate: LocalDate = LocalDate.of(2027, 7, 20)
// Call the function to get the number of completed months
val totalMonths = getMonthsBetween(startdate, enddate)
println("Start Date: $startdate")
println("End Date: $enddate")
println("Total Months: $totalMonths")
}
/**
* Calculates the number of completed calendar months between two LocalDates.
*
* @param startDate The starting LocalDate.
* @param endDate The ending LocalDate.
* @return The number of full months between the dates.
*/
fun getMonthsBetween(startDate: LocalDate, endDate: LocalDate): Int {
// Validate that the start date is not later than the end date
require(!startDate.isAfter(endDate)) { "Start date cannot be later than the end date." }
// 1. Calculate the base month difference using years and months
val yearsDiff = endDate.year - startDate.year
val monthsDiff = endDate.monthValue - startDate.monthValue
var totalMonths = (yearsDiff * 12) + monthsDiff
// 2. Adjust if the end day is earlier in the month than the start day
// (meaning the final month hasn't fully elapsed yet)
if (endDate.dayOfMonth < startDate.dayOfMonth) {
totalMonths -= 1
}
return totalMonths
}
/*
run:
Start Date: 2026-01-15
End Date: 2027-07-20
Total Months: 18
*/
