# Explanation for Beginners: Writing a Leap Year Function in MATLAB Let's break down what you need to do, **step by step**, as if you know nothing about MATLAB or leap years. --- ## 1. **What is a Leap Year?** A **leap year** is a year with an extra day (February 29). The rules are: - If a year is divisible by 4, it **might** be a leap year. - If that year is also divisible by 100, it is **not** a leap year, **unless**: - The year is also divisible by 400, then **it is** a leap year. **Examples:** - 2000 is a leap year (divisible by 400) - 1900 is NOT a leap year (divisible by 100 but not by 400) - 2004 is a leap year (divisible by 4, not by 100) --- ## 2. **What is MATLAB?** **MATLAB** is a programming language used for math and engineering. You write instructions in files called **.m files**. --- ## 3. **What is a Function in MATLAB?** A **function** is a reusable piece of code. You tell MATLAB to run it by typing its name. --- ## 4. **What Do You Need to Do?** You need to **write a function** called `leapyear` that: - Takes in a year (or several years) as input. - Tells you if each year is a leap year (1 for true, 0 for false). --- ## 5. **How to Write This Function?** ### The Rules in MATLAB Code: You will check for each year: 1. If the year is divisible by 4 (`mod(year, 4) == 0`) 2. But NOT divisible by 100 (`mod(year, 100) ~= 0`) 3. OR is divisible by 400 (`mod(year, 400) == 0`) If these conditions are met, it's a leap year. --- ### Example MATLAB Function ```matlab function output = leapyear(year) % output is 1 if leap year, 0 if not output = (mod(year,4) == 0 & mod(year,100) ~= 0) | (mod(year,400) == 0); end ``` - `mod(a, b)` means "remainder after dividing a by b". - `==` means "equals". - `~=` means "not equal". - `&` means "and". - `|` means "or". --- ## 6. **How to Use the Function?** - Save your function in a file called **leapyear.m** - In MATLAB, you can use it like this: ```matlab leapyear(2000) % Will return 1 leapyear(1900) % Will return 0 leapyear([2000, 1900, 2004]) % Will return [1 0 1] ``` --- ## 7. **Counting Leap Years in a Range** To count how many leap years are between 1492 and 3097: ```matlab sum(leapyear(1492:3097)) ``` - `1492:3097` creates a list of all years from 1492 to 3097. - `leapyear(1492:3097)` gives a list of 1's and 0's, one for each year. - `sum(...)` adds up all the 1's, telling you how many leap years there are. --- ## 8. **How to Submit?** - Save your function in a file named `leapyear.m`. - Make sure the file is in the right folder so MATLAB can find it. --- ## 9. **Grading** - You get points for having the correct function and for counting the number of leap years correctly. --- If you have any questions about any step, **ask away!**