// This is all about string class --> String is a class in java but use as a datatype...

package string.stringclass;

// import string package from java.lang class...

import java.lang.String;

public class StringExample {

public static void main(String[] args) {

// declare string form perform opertations and used method on it...

String str = "Hello World";

// find length of a string...

int strLength = str.length(); // space all count when length is calculated...

System.out.println(strLength);

// converting string according to the case...

String upperCaseStr = str.toUpperCase(); // Converting into Uppercase...

System.out.println(upperCaseStr);

String lowerCaseStr = str.toLowerCase(); // Converting into Lowercase...

System.out.println(lowerCaseStr);

// removing white space arround the string...

String trimmedStr = str.trim();

System.out.println(trimmedStr);

// creating substring from given string...

String subStr1 = str.substring(2,5); // From index 2

System.out.println(subStr1);

String subStr2 = str.substring(4); // From Index 4

System.out.println(subStr2); // till end of the string..

// checking string whether it starts and ends with specified str...

boolean startWith = str.startsWith("Hel");

System.out.println(startWith); // true or false

boolean endWith = str.endsWith("ld");

System.out.println(endWith);

boolean startWith1 = str.startsWith("lo");

System.out.println(startWith1); // true or false

boolean endWith2 = str.endsWith("rl");

System.out.println(endWith2); // true or false

// find the characters in the given string...

char findChar = str.charAt(2);

System.out.println(findChar); // returns the character which is on the index 2...

// replace a given string with the another string...

String replacedStr = str.replace('o', 'X'); // replaces all o with X...

System.out.println(replacedStr); // HExl WrXld

// valueOf() method --> it convert the given datatype into a string...

Integer num = 98;

String convertedNum = String.valueOf(num);

System.out.println(convertedNum); // 98 --> but now it is a string...

String modifiedString = convertedNum.concat( " ").concat(str);

System.out.println(modifiedString); // 98 Hello World

/* intern() method --> it return the string if exist in the string pool

if not present in the string pool then it create the string with new reference...*/

String s3 = "Hello";

String s4 = "Hello";

String s5 = s3.intern();

System.out.println(s5 == s4); // true

String s6 = "Hello";

// String s7 = "Ravi";

String s8 = "Ravi".intern();

System.out.println(s8 == s6); // false

// comparision of strings...

// using equals() method...

boolean eq1 = s3.equals("Hello");

System.out.println(eq1); // true

boolean eq2 = s3.equals("hello");

System.out.println(eq2); // false --> because java is case sensitive...

boolean eq3 = s3.equalsIgnoreCase("hello");

System.out.println(eq3); // true

// using == operator...

boolean eq4 = (s3 == "Hello");

System.out.println(eq4); // false --> because == checks for refernece...

boolean eq5 = (s3 == s4);

System.out.println(eq5); // true --> both are pointing to same object

// using compareTo() method...

int cmp = s3.compareTo("World"); // s3 = "Hello"...

/* returns -1 if first

argument is less than second, 0 if equal and

+1 if first argument is greater */

System.out.println(cmp); // -1

// toString() method...

String strObj = s3.toString();

System.out.println(strObj); // Hello --> convert string into object...

// indexOf() method...

int indx = s3.indexOf('l');

System.out.println(indx); // 2 --> at which first we found 'l'...

int indx1 = s3.indexOf('w');

System.out.println(indx1); // -1 --> not found 'w'...

int indx2 = s3.indexOf('l', 2);

System.out.println(indx2); // 3 --> finding starts from 2nd...

// lastIndexOf() method...

int lstIndx = s3.lastIndexOf('o');

System.out.println(lstIndx); // 4 --> it will return from left...

// --> mostly used method of string are covered.. <--

}

}