Java String charAt() Method

The Java String charAt() method returns the character at the specified index. The index value should lie between 0 and length() – 1. Let us check more points about the String charAt() method in Java.

Syntax of charAt() Java method

public char charAt(int index)

Parameters

• index: Index of the character to be returned.

Return Type

• Returns the character at the specified position.

Exceptions

• StringIndexOutOfBoundsException– If the index is negative or greater than the length of the String.

Example of Java String charAt()

The following examples demonstrate how to use charAt() method:

Example 1:

To show the working of the charAt() method 

Java

// Java program to demonstrate
// working of charAt() method

// driver class
class Gfg {
    // main function
    public static void main(String args[])
    {
        String s = "Welcome! to Geeksforgeeks Planet";

        char ch = s.charAt(3);
        System.out.println(ch);

        ch = s.charAt(0);
        System.out.println(ch);
    }
}

Output

c
W

Example 2:

The following program demonstrates the StringIndexOutOfBoundsException.

Java

// Java program to demonstrate
// working of charAt() method

// Driver class
class Gfg {
    // main function
    public static void main(String args[])
    {
        String s = "abc";

        char ch = s.charAt(4);
        System.out.println(ch);
    }
}

Output

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 4
    at java.lang.String.charAt(String.java:658)
    at Gfg.main(File.java:9)

Programs for charAt Java Method

1. Accessing the First and Last Character using the charAt() Java method

Java

// Java Program to implement
// Accessing the First and Last Character
import java.io.*;

// driver class
class GFG {
    // main function
    public static void main(String[] args)
    {
        String str = "GeeksforGeeks";
        int len = str.length();

        // First Element
        System.out.println("First Element: "
                           + str.charAt(0));

        // Last Element
        System.out.println("First Element: "
                           + str.charAt(len - 1));
    }
}

Output

First Element: G
First Element: s

2. Print Characters Presented at Odd Positions and Even Positions using charAt() Java method

Java

// Java Program to implement
// Print Characters Presented at
// Odd Positions and Even Positions
import java.io.*;

// Driver Class
class GFG {
    // main function
    public static void main(String[] args)
    {
        String str = "GeeksforGeeks";

        // Odd Positions
        System.out.println("Odd Positions");
        for (int i = 0; i < str.length(); i += 2) {
            System.out.print(str.charAt(i));
        }

        System.out.println("\n");

        // Even Positions
        System.out.println("Even Positions");
        for (int i = 1; i < str.length(); i += 2) {
            System.out.print(str.charAt(i));
        }
    }
}

Output

Odd Positions
GesoGes

Even Positions
ekfrek

3. Counting Frequency of a Character in a String using Java charAt() method

Java

// Java Program to implement
// Counting Frequency of a Character
// in a String
import java.io.*;

// Driver Class
class GFG {
    // main function
    public static void main(String[] args)
    {
        String str = "GeeksforGeeks";
        int count = 0;

        for (int i = 0; i < str.length(); i++) {
            // Counting e in string
            if (str.charAt(i) == 'e')
                count++;
        }

        // printing occurrence
        System.out.println("Count the occurrence of e : "
                           + count);
    }
}

Output

Count the occurrence of e : 4

References

To know more about more String classes refer to the article String Class in Java.