How to Write Method Headers

2 min read•july 11, 2024

Milo Chang

AP Computer Science A 💻

130 resources

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Look at this chunk of code: 💻

public class Cats
{
   public int countNumFeet (int numCats)
   {
        return 4*numCats;
   }

   // There may be instance variables, constructors, and other methods not
   // shown.
}

Can you identify the method header? 🤔

That's right! 👏 It's "public int countNumFeet (int numCats)"! 🐱

Breaking it Down: 🔍

The keyword "public" means that this method can be accessed from other classes.

It can be replaced by the word "private" to give you:

private int countNumFeet (int numCats)

Putting "private" means that the method can only be accessed within the "Cats" class

The keyword "int" tells you what this method returns when it is called.

In this case, it returns an integer value after it is called
It can be replaced by "double", "boolean", "String", or the name of a class if the method returns an object
If the word "void" is there instead of the other options, this means the method doesn't return anything

The word "countNumFeet" is the name of the method.

This can be replaced with anything without changing what the method does
It's best if you make the name of the method something that lets people easily know what it's doing

The "int numCats" tells you what is being passed into this method.

In the example, an integer called "numCats" is being passed in
You can have a method that has nothing being passed in:

public int countNumFeet ()

You can also have a method that has multiple parameters passed in:

public int countNumFeet (int numCats, int numEars, boolean isAngry)

Method headings may also include the phrases "static" or "abstract", but this will be discussed in later articles. 

Try it out! 😃

#1) Write the header for a method that can only be accessed within the class it's declared in. This method takes in a String called "text" and doesn't return anything. Call your method "example1". (Scroll down for the answer)

#2) Write the header for a method that can be accessed from other classes. This method takes nothing in and returns a boolean. Call your method "example2". (Scroll down for the answer)

#3) Write the header for a method that can be accessed from other classes. This method takes in a boolean "testPassed" and an integer "score". It returns a String. Call your method "example3". (Scroll down for the answer)

Answers: ✔

#1) private void example1 (String text)#2) public boolean example2 ()#3) public String example3 (boolean testPassed, int score)

Summary: 🎉✨

You can write a method header with just a few simple steps.

Choose public or private
Choose what the method returns: void (nothing), int, double, boolean, String, or the name of a class
Choose the name of the method
Choose what parameters to pass into the method