void setup() {
 


  Serial.begin(9600);


  // 1. setCharAt(index, c)
  String str1 = "Hello";
  str1.setCharAt(1, 'a');
  Serial.print("setCharAt: ");
  Serial.println(str1); 

  // 2. startsWith(S2)
  String str2 = "Hello";
  if (str2.startsWith("He")) { 
    Serial.println("startsWith: Starts with He");
  }

  // 3. substring(index):
  String str3 = "Hello";
  String substr1 = str3.substring(2);
  Serial.print("substring(index): ");
  Serial.println(substr1); 

  // 4. substring(index, to):
  String substr2 = str3.substring(1, 4);
  Serial.print("substring(index, to): ");
  Serial.println(substr2); 

  // 5. toCharArray(buffer, len):
  char buf[6];
  str3.toCharArray(buf, 6);
  Serial.print("toCharArray: ");
  Serial.println(buf); 

  // 6. toFloat():
  String str4 = "123.45";
  float num1 = str4.toFloat();
  Serial.print("toFloat: ");
  Serial.println(num1); 

  // 7. toInt():
  String str5 = "123";
  int num2 = str5.toInt();
  Serial.print("toInt: ");
  Serial.println(num2); 

  // 8. toLowerCase():
  String str6 = "Hello";
  str6.toLowerCase();
  Serial.print("toLowerCase: ");
  Serial.println(str6);

  // 9. toUpperCase():
  String str7 = "Hello";
  str7.toUpperCase();
  Serial.print("toUpperCase: ");
  Serial.println(str7); 

  // 10. trim():
  String str8 = "  Hello ";
  str8.trim();
  Serial.print("trim: ");
  Serial.println(str8); 

  // 11. charAt(n):
  String str9 = "Hello";
  char ch = str9.charAt(1);
  Serial.print("charAt: ");
  Serial.println(ch); 

  // 12. compareTo(S2):
  String str10 = "Hello";
  String str11 = "World";
  int result = str10.compareTo(str11);
  Serial.print("compareTo: ");
  Serial.println(result); 

  // 13. concat(S2):
  String str12 = "Hello ";
  String str13 = "World";
  str12.concat(str13);
  Serial.print("concat: ");
  Serial.println(str12); 

  // 14. endsWith(S2):.
  String str14 = "Hello";
  if (str14.endsWith("lo")) {
    Serial.println("endsWith: Ends with lo");
  }

  // 15. equals(S2): 
  String str15 = "Hello";
  String str16 = "Hello";
  if (str15.equals(str16)) {
    Serial.println("equals: Strings are equal");
  }

  // 16. equalsIgnoreCase(S2):  
  String str17 = "Hello";
  String str18 = "hello";
  if (str17.equalsIgnoreCase(str18)) {
    Serial.println("equalsIgnoreCase: Strings are equal ignoring case");
  }

  // 17. getBytes(buffer, len):
  byte buf2[6];
  str17.getBytes(buf2, 6);
  Serial.print("getBytes: ");
  Serial.write(buf2, 5); 
  Serial.println();

  // 18. indexOf(S):
  int index1 = str17.indexOf('e');
  Serial.print("indexOf: ");
  Serial.println(index1); 

  // 19. lastIndexOf(S):
  int index2 = str17.lastIndexOf('l');
  Serial.print("lastIndexOf: ");
  Serial.println(index2); 

  // 20. length():
  int len = str17.length();
  Serial.print("length: ");
  Serial.println(len); 

  // 21. remove(index):.
  String str19 = "Hello";
  str19.remove(1);
  Serial.print("remove(index): ");
  Serial.println(str19); 

  // 22. remove(index, count):
  String str20 = "Hello";
  str20.remove(1, 2);
  Serial.print("remove(index, count): ");
  Serial.println(str20); 

  // 23. replace(A, B):
  String str21 = "Hello";
  str21.replace('l', 'x');
  Serial.print("replace: ");
  Serial.println(str21); 

  // 24. reserve(count):
  String str22;
  str22.reserve(10);
  str22 = "Hello";
  Serial.print("reserve: ");
  Serial.println(str22); 
}


void loop() {
  // put your main code here, to run repeatedly:

}