String [Manipulating methods][StringBuffer Class methods]

String : A built in class, whose object is used to store the set of characters, is called as string.

Example :
String S1=new String("Hello");
or
String S1="Hello";

String manipulation methods:

1. length() :- This method is used to return the number of characters of a given string.
2. trim() :-  This method is used to trim or remove the white spaces from Right Hand Side and Left Hand Side of given string.
3. toUpperCase() :- This method is used to convert the given string in Upper case.
4. toLowerCase() :- This method is used to convert the given string in Lower case. 
5. equals() :- This method is used to compare two string according to there ASCII value for equality.
   

   [It returns true if both the string are same & otherwise return false]

6. CompareTo() :- This method is also used to compare two string according to ASCII values.
   

   [It's return type is Integer]

   Example:
   int i=s1.compareTo(s2);
   
   if it return > 0 value then s2>s1
   if it return < 0 value then s1>s2
   if it return = 0 value then s1=s2
   
   

7. CompareToIgnoreCase() :- It work is same as above method with ignoring the case sensitivity.

Write a program to implement all the methods of string class.

class str
{
 public static void main(String args[])
 
 {
  String s1="Good morning";
  System.out.println(s1);
  
  String s2=s1.trim();
  System.out.println(s2);
  
  System.out.println("length of s1="+s1.length());
  System.out.println("length of s2="+s2.length());
  
  String s3=s2.toUpperCase();
  String s4=s2.toUpperCase();
  System.out.println("S3= "+s3);
  System.out.println("S4= "+s4);
  
  if(s3.equals(s4))
  System.out.println("Both the string are same");
  else
  System.out.println("Both the string are not same");
  
  int i=s3.compareToIgnoreCase(s4);
   if(i<0 s4="" system.out.println="">s3");
   else if(i>0)
   System.out.println("s3>s4");
   else if(i==0)
   System.out.println("s3 = s4"); 
 }
}

Note : String is a native or peer class, so the changes occurred in same other location.

To perform the changes on same location, we have to follow the StringBuffer class.

It dynamically increment or decrements the size of String object.

StringBuffer class methods

1. append(String) :- This method is used to join or append the new string in previous string.
2. insert(index, string) :- This method is  used to insert the new string on the specified index of previous string.
3. setCharAt(index, char) :- This method set or replace the specified index character with the new character.
4. reverse() :- This method is used to convert the given string in reverse.

Write a program to implement all the methods of stringBuffer class.

class str1
{
 public static void main(String args[])
 {
  StringBuffer sb=new StringBuffer("Hello morning");
  System.out.println(sb);
  
  sb.append("Bye");
  System.out.println(sb);
  
  sb.insert(13, " ");
  System.out.println(sb);
  
  sb.insert(6, "Good");
  System.out.println(sb);
  
  sb.insert(10, " ")
  System.out.println(sb);
  
  sb.setCharAt(10,"_");
  System.out.println(sb);
  
  
  System.out.println(sb.reverse());
 }
}