Java String charAt() method
Syntax and Examples

Introduction

Strings are fundamental in Java and often need to be manipulated. The charAt() method provides a way to access individual characters within a string by their index.

Syntax

	public char charAt(int index)
	

Parameters

Parameter	Description
index	The index of the character to retrieve. This is a zero-based index, meaning the first character is at index 0.

Return Value

The charAt() method returns a char representing the character at the specified index in the string.

Examples

Example 1: Retrieving the First Character

This example demonstrates how to get the first character of a string using an index of 0.

	
	public class CharAtExample {
	    public static void main(String[] args) {
	        String str = "Hello";
	        char firstChar = str.charAt(0);
	        System.out.println("The first character is: " + firstChar);
	    }
	}
	
	

The first character is: H

Here, we declare a string str as "Hello". Then, we call the charAt(0) method to retrieve the character at index 0 which is 'H'. Finally, it prints the retrieved character.

Example 2: Retrieving a Character from the Middle

This example shows how to access a specific character in the string by providing its index. Let's retrieve the character at index 2.

	
	public class CharAtExample {
	    public static void main(String[] args) {
	        String str = "Java";
	        char middleChar = str.charAt(2);
	        System.out.println("The character at index 2 is: " + middleChar);
	    }
	}
	
	

The character at index 2 is: v

In this example, we take the string 'Java' and access the element at index 2 which corresponds to the character 'v'. The method returns this value.

Example 3: Handling Index Out of Bounds

This demonstrates what happens when you try to access an invalid (out-of-bounds) index. Attempting to retrieve a character beyond the string's length will result in a StringIndexOutOfBoundsException.

	
	public class CharAtExample {
	    public static void main(String[] args) {
	        String str = "Hello";
	        try {
	            char outOfBoundsChar = str.charAt(10); // Index 10 is out of bounds.
	            System.out.println("Character at index 10: " + outOfBoundsChar);
	        } catch (IndexOutOfBoundsException e) {
	            System.out.println("Error: Index Out of Bounds - " + e.getMessage());
	        }
	    }
	}
	
	

	Error: Index Out of Bounds - String index out of range [0-4]
	

This example uses a try-catch block to handle the potential IndexOutOfBoundsException. Since we're trying to access an element at index 10 in "Hello" (which is only 5 characters long), Java throws this exception, which is then caught and displayed.

Example 4: Iterating Through a String

Here's how you can use `charAt()` to iterate through all the characters in a string.

	
	public class CharAtExample {
	    public static void main(String[] args) {
	        String str = "World";
	        for (int i = 0; i < str.length(); i++) {
	            char currentChar = str.charAt(i);
	            System.out.println("Character at index " + i + ": " + currentChar);
	        }
	    }
	}
	
	

	Character at index 0: W
	Character at index 1: o
	Character at index 2: r
	Character at index 3: l
	Character at index 4: d
	

This loop iterates from index 0 to the last character (length - 1). In each iteration, it retrieves a character using charAt(i) and prints its value. This is a common technique when you need to process each individual character in a string.