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Java StringBuilder charAt() method with example

StringBuilder Class charAt() method: Here, we are going to learn about the charAt() method of StringBuilder Class with its syntax and example.
Submitted by Preeti Jain, on December 21, 2019

StringBuilder Class charAt() method

• charAt() method is available in java.lang package.
• charAt() method is used to return the character value of the given index and array indexing starts from 0 (i.e. first character value will be located at index 0 and second character value will be located at index 1 and so..on).
• charAt() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• charAt() method may throw an exception at the time of returning the character of non-indexed.
  IndexOutOfBoundsException - This exception may throw when the given argument is greater than the length or denotes negative value.

Syntax:

    public char  charAt(int indices);

Parameter(s):

• int indices – represents the index of the returned char value.

Return value:

The return type of this method is char, it returns the char value of the given index.

Example:

// Java program to demonstrate the example 
// of char  charAt(int indices) method of StringBuilder 

public class CharAt {
    public static void main(String[] args) {

        // Creating an StringBuilder object
        StringBuilder st_b = new StringBuilder("Java");
        System.out.println("st_b = " + st_b);

        // By using charAt(1) method to display the character of
        // given index 1 i.e. 'a'
        System.out.println("st_b.charAt(1) = " + st_b.charAt(1));

        // Creating another StringBuilder object
        st_b = new StringBuilder("Programming");
        System.out.println("st_b = " + st_b);

        // By using charAt(11) method throw an exception i.e.
        // no such index exists
        // System.out.println("st_b.charAt(11) = "+st_b.charAt(11));
    }
}

Output

st_b = Java
st_b.charAt(1) = a
st_b = Programming