String manipulation in java

Java String

1.In c/c++ string are stored in array of character terminated by null character.

2.But in java have inbuilt class string.

3.Class string define in java.lang package.

4.String in java are immutable that means you can not modify any character from a string.

5.In c/c++ we can modify string.

     Declaring and constructing string:

Four ways to construct string.

1.  String s1=new String(“Good Morning”);

2.  String s2;

      S2=“Good Morning”;

3.   char []ar={‘C’,’H’,’O’,’U’,’B’,’E’,’Y’};

       String S3=new String(ar);

4.   String s4=new String();  //it creates empty or null string

Writing a string:

System.out.println(s1);

Or

System.out.print(s1);

S1=s2;

Copying one string into other:

We know that string is immutable and can not be modified, it is true.This case is treat as exception.Actually string is an object and variable name are object reference hence it is possible for a given reference to point to another string.

Comparing string:

•There is two method to compare string.

•first is

S1.equals(s2);//case sensitive

S1.equalsIgnoreCase(s2);//ignore case

•These method gives Boolean result i.e. true or false.

to another string.  

•Second type of comparison:

S1.compareTo(s2);

•It returns integer value ,+ve,zero,-ve.

•If we want to know that one string is less than , equal to or greater than another string lexicographicaly then use this method.

Example string Program:

import java.lang.*; 
/* this package by default included,
if i dont write this line then it will not give error.*/
class string2
{
public static void main(String ar[])
{
 String s1=new String("Rahul");
 
 String s2=new String("sant");
 
String s3=new String("choubey");

 String s4=new String(“choubey");

 int i,j,k;

 i=s4.compareTo(s1);

 j=s4.compareTo(s3);

 k=s4.compareTo(s2);

 System.out.println("s4&s1="+i);

System.out.println("s4&s3="+j);

System.out.println("s4&s2="+k);
}
}