Untitled

public class StringMethodsDemo {

    public static void main(String[] args) {
        String str = "Hello, World!";

        // 1. Length
        System.out.println("Length: " + str.length()); 
        if(str.charAt(0)=='H'){
            str.setCharAt(0, 'p');
        };
        // 2. charAt
        System.out.println("Character at index 0: " + str.charAt(0)); 

        // 3. Substring
        System.out.println("Substring from index 7: " + str.substring(7)); 
        System.out.println("Substring from index 0 to 5: " + str.substring(0, 5)); 

        // 4. Concatenation
        System.out.println("Concatenated string: " + str.concat(" How are you?")); 

        // 5. toUpperCase and toLowerCase
        System.out.println("Uppercase: " + str.toUpperCase()); 
        System.out.println("Lowercase: " + str.toLowerCase()); 

        // 6. indexOf and lastIndexOf
        System.out.println("Index of 'o': " + str.indexOf('o')); 
        System.out.println("Last index of 'o': " + str.lastIndexOf('o')); 

        // 7. replace
        System.out.println("Replacing 'l' with 'L': " + str.replace('l', 'L')); 

        // 8. startsWith and endsWith
        System.out.println("Starts with 'Hello': " + str.startsWith("Hello")); 
        System.out.println("Ends with 'you?': " + str.endsWith("you?")); 

        // 9. trim
        String strWithSpaces = "   Hello, World!   ";
        System.out.println("Trimmed string: " + strWithSpaces.trim()); 

        // 10. split
        String[] words = str.split(", ");
        System.out.println("Split string:");
        for (String word : words) {
            System.out.println(word);
        }

        // 11. equals and equalsIgnoreCase
        System.out.println("Equals 'Hello, World!': " + str.equals("Hello, World!")); 
        System.out.println("EqualsIgnoreCase 'hello, world!': " + str.equalsIgnoreCase("hello, world!")); 
    }
}