Small Basic Example: Leap Year Checker

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Leap Year Checker

Overview

For example, let’s say you want to create a program that checks whether a given year’s a leap year or not. It’s a leap year if the year’s evenly divisible by 4. But if it’s evenly divisible by 100, then it also needs to be evenly divisible by 400. The Figure shows you a flowchart of what you’d need to test for.

 

Figure: A flowchart for checking if a given year’s a leap year

Here are three examples of these rules:

  1. Year 2020 is divisible by 4. Since it isn’t evenly divisible by 100, it’s a leap year!
  2. Year 2100 is divisible by 4. Because it’s evenly divisible by 100, you need to check its divisibility by 400. Since it isn’t evenly divisible by 400, it’s not a leap year.
  3. Year 2400 is divisible by 4. Because it’s evenly divisible by 100, you’ll need to check its divisibility by 400. Since it’s evenly divisible by 400, it’s a leap year!

Assignment

Create a program that implements this flowchart (see code below). Also, you’ll find the output from three sample runs.

Code

 

1   ' Determines if a given year is a leap year

2   TextWindow.Write( "Enter a year (like 2050): ")

3   year = TextWindow.ReadNumber()

4   If ( Math.Remainder( year,4) <> 0 ) Then  ' Not divisible by 4

5     TextWindow.WriteLine(year + " isn't a leap year.")

6   Else       ' divisible by 4

7    If ( Math.Remainder( year,100) <> 0 ) Then ' Not divisible by 100

8      TextWindow.WriteLine( year + " is a leap year.")

9    Else     ' divisible by 4 and 100

10     If ( Math.Remainder( year,400) = 0 ) Then ' Divisible by 400

11       TextWindow.WriteLine( year + " is a leap year.")

12     Else   ' Divisible by 4 and 100, but not 400

13       TextWindow.WriteLine( year + " isn't a leap year.")

14     EndIf

15    EndIf  

16  EndIf

Output Examples

Enter a year (like 2050): 2020

2020 is a leap year.

Enter a year (like 2050): 2100

2100 isn’t a leap year.

Enter a year (like 2050): 2400

2400 is a leap year.

Explanation

After getting the year from your user, Small Basic checks if the year’s divisible by 4 (Line 7). If not, then your program runs the statement on Line 8 and ends.

If the input year’s divisible by 4, your program moves on to Line 10. If the year isn’t evenly divisible by 100, then it’s a leap year; the program runs the statement on Line 11 and then ends.

If the entered year’s evenly divisible by both 4 and 100, then your program runs Line 13, which divides the year by 400. If the input year’s divisible by 400, it’s a leap year; your program runs the statement on Line 14 and then ends.

If it isn’t divisible by 400, then the input year isn’t a leap year; your program runs the statement on Line 16 and then ends.

Learn more about Small Basic here:

https://blogs.msdn.com/smallbasic

Enjoy learning how to program with Small Basic, and have a Small and Basic week!

   - User Ed & Majed Marji