AP Computer Science A

How to Write Method Headers

3 min readLast Updated on July 11, 2024

Milo Chang

Milo Chang

Milo Chang

Milo Chang

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! 😃

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.

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

That's it! You're ready to start writing your own method headers! 👏

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