📓3.5: Writing Methods

Table of Contents

📖 This page is a condensed version of CSAwesome Topic 3.5

Methods

A method is a named block of code that performs a specific task. Methods are used to define the behaviors of a class and can be called from other parts of a program.

Why Use Methods?

  • Reusability: Write code once, use it multiple times.
  • Organization: Break large programs into smaller, manageable pieces.
  • Readability: Clear names make code easier to understand.

Method Structure 

accessModifier returnType methodName(parameters) {
    // method body
}

Example:

public void bark() {
    System.out.println("Woof!");
}

Returning Values

Some methods compute a result and return it.

public int getAge() {
    return age;
}

The returnType matches the type of value returned. Use void if the method does not return anything.

Parameters

  • Allow you to pass information into a method.
  • Declared in parentheses after the method name.

Example:

public void setName(String newName) {
    name = newName;
}

Calling Methods

Use dot notation:

Dog myDog = new Dog("Buddy", 3);
myDog.bark();
myDog.setName("Max");
System.out.println(myDog.getAge());

Summary

  • Methods define the actions a class can perform.
  • Use parameters to pass information and return types to send results back.
  • Use void when no value is returned.

AP Practice

Question</summary>

Which of the following correctly defines a method that takes no parameters and returns nothing?

  • A. public bark() { ... }
  • B. public void bark { ... }
  • C. public void bark() { ... } ✅
  • D. public bark(void) { ... }

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Acknowledgement

Content on this page is adapted from Runestone Academy - Barb Ericson, Beryl Hoffman, Peter Seibel.