;s Statement String1 ds igys ‘b’ Character ds Index Number dks Return djrk gSA
string1.indexOf(‘b’, n);
;s Statement String1 ds n Characters ds ckn igys ‘b’ Character ds Index Number
dks Return djrk gSA
String.ValueOf(ValueM);
;s Statement Parameter ValueM dks String Representation esa Convert djds
Return djrk gSA
buesa ls dqN String Methods dks ge ,d Applet Program esa Use djds mldk Output ns[k ldrs gSaA Applet Program dks fuEukuqlkj Develop fd;k tk ldrk gS%
Program
// Source File : StringMethodApplet.java // Compiled File: StringMethodApplet.Class // Imports
import java.applet.*;
import java.awt.*;
publicclass StringMethodApplet extends Applet {
TextField textBox = new TextField(40); String str;
publicvoid init() {
add(textBox); }
publicvoid paint(Graphics g) { boolean yes; char characterAtPosition; int strLength; str = textBox.getText(); str = str.toLowerCase();
g.drawString("toLowerCase Method : " + str, 20, 80); str = str.toUpperCase();
Java in Hindi
g.drawString("toUpperCase Method : " + str, 20, 60); str = str.trim();
g.drawString("trim Method : " + str, 20, 100); yes = str.equals("Man Mohan");
g.drawString("equals Method : " + yes, 20, 140); yes = str.equalsIgnoreCase("Man Mohan"); g.drawString("equals Method : " + yes, 20, 160); str = str.replace('a', 'i');
g.drawString("replace Method : " + str, 20, 120); strLength = str.length();
g.drawString("length Method : " + strLength, 20, 180); characterAtPosition = str.charAt(4);
g.drawString("charAt Method : " + characterAtPosition, 20, 200); strLength = str.compareTo("Man Mohan");
g.drawString("compareTo Method : " + strLength, 20, 220); str = str.concat(" Lal");
g.drawString("concat Method : " + str, 20, 240); str = String.valueOf(1000);
g.drawString("String.valueOf Method : " + str, 20, 260); }
publicboolean action(Event evnt, Object obj) { repaint(); returntrue; } } Output
Java in Hindi
GUI esa fdlh Number dks Display djuk gks ;k fdlh Character dks] nksuksa dks gh String Format esa gh Display djuk iMrk gSA fdlh Numerical eku dks Text Format ;k String Format esa Convert fd, fcuk ge mls GUI Application Window ;k fdlh Applet ij
Display ugha dj ldrs gSaA
blfy, tc gesa fdlh Applet esa fdlh Numerical eku dks Display djuk gksrk gS] rc ml eku dks Display djus ls igys gesa ml eku dks String Object esa Convert djuk t:jh gksrk gSA
fdlh Numerical eku dks String Object esa Convert djus ds fy, gesa String Class ds
valueOf() Method dk iz;ksx djuk iMrk gS vkSj ftl eku dks String esa Convert djuk gksrk gS] ml eku dks Argument ds :i esa valueOf() Method ds Parenthesis esa nsuk gksrk gSA
fiNys Program esa eku 1000 dks geus blh rjhds ls Applet ij Display fd;k gSA blh rjg ls compareTo() String Method dk iz;ksx djds ge Strings ds Array dh Sorting dj ldrs gSaA
Program
class StringSorting {
static String name[] = { "Madhav", "Krishna", "Kanhaiya", "Balgopal", "Nandlal" };
Java in Hindi
{
int size = name.length; String temp = null;
for(int i = 0; i < size; i++) {
for(int j = i+1; j < size; j++) {
if(name[j].compareTo(name[i]) < 0) {
//swap the strings
temp = name[i];
name[i] = name[j];
name[j] = temp; }
} }
for( int i = 0; i<size; i++) {
System.out.println(name[i]); } } Output Balgopal Kanhaiya Krishna Madhav Nandlal
bl Program esa for() Loop dk iz;ksx fd;k x;k gSA Looping ,d Control Statement gS] ftlds ckjs esa ge vxys v/;k; esa i<saxsA
StringBuffer Class
StringBuffer String Class dh ,d Peer Class gSA ;kuh String Class Fixed_Length
dh String Object Create djrk gS] tcfd StringBuffer Flexible Length dk String Object Create djrk gS] ftlds Contents o Length nksuksa dks Modify fd;k tk ldrk gSA
bl Object dh String ds chp esa ge ubZ String Insert dj ldrs gSa lkFk gh fdlh ubZ String
dks bl String Object dh String ds End esa Append Hkh dj ldrs gSaA blds Object ds lkFk ge fuEu String Methods dks Use dj ldrs gSa tks fd lokZf/kd Use fd, tkrs gSa&
string1.setChartAt(n, ‘p’)
;s Statement string1 ds nth Character dks Modify djds ‘p’ dj nsrk gSA
Java in Hindi
;s Statement string2 ds vUr esa string1 dks Append dj nsrk gSA
string1.insert(n, string2)
;s Statement string1 ds nth Character ij string2 dks Insert dj nsrk gSA
string1.setLength(n)
;s Statement string1 dh length dks n ds cjkcj Set dj nsrk gSA ;fn
n<string1.length gks rks string1 Truncate gks tkrh gSA ;fn n>String 1.length gks rks
string1 esa zeros Add gks tkrs gSaA
bUgsa Use djrs gq, ge fuEukuqlkj ,d Program cuk ldrs gSa&
Program
class StringManipulation {
publicstaticvoid main(String args[]) {
StringBuffer string1 = new StringBuffer("OOPS with JAVA"); System.out.println("Original String : " + string1);
//Obtaining string length
System.out.println("Length of String : " + string1.length());
//Accessing characters of string
for(int i=0; i<string1.length(); i++) {
int p = i + 1;
System.out.println("Character at position : " + p + " is " + string1.charAt(i));
}
//Inserting a string in middle of string1
String string2 = new String(string1.toString()); int pos = string2.indexOf(" with");
string1.insert(pos, " Concepts ");
System.out.println("Modified string : " + string1);
//Modifying characters
string1.setCharAt(6, '_');
System.out.println("String now : " + string1);
//Appending a string at the end
string1.append(" Programming");
System.out.println("Appended string : " + string1); }
}
Java in Hindi
Original String : OOPS with JAVA Length of String : 14 Character at position : 1 is O Character at position : 2 is O Character at position : 3 is P Character at position : 4 is S Character at position : 5 is Character at position : 6 is w Character at position : 7 is i Character at position : 8 is t Character at position : 9 is h Character at position : 10 is Character at position : 11 is J Character at position : 12 is A Character at position : 13 is V Character at position : 14 is A
Modified string : OOPS Concepts with JAVA String now : OOPS C_ncepts with JAVA
Appended string : OOPS C_ncepts with JAVA Programming
Command Line Arguments
dbZ ckj ,slh ifjfLFkfr;ka gksrh gSa fd tc ge pkgrs gSa fd gekjk Program Command Prompt
ij gekjs }kjk fn, x, Input ds vk/kkj ij fofHkUu izdkj ds Operations Perform djsA fdlh izksxzke ls ;s fof”k’Vrk izkIr djus ds fy, gesa ,d ,sls tkok Concept dks Use djuk gksrk gS]
ftls Command Line Arguments dgrs gSaA
Command Line Arguments os eku gksrs gSa] tks fdlh Program dks Command Prompt ij
Run djrs le; Parameters ds :i esa Program dks iznku fd, tkrs gSaA mnkgj.k ds fy, tc ge fuEukuqlkj Hello World Program dks Run djrs gSa %
C:jdk\bin\> java HelloWorld
rc ;gka ge HelloWorld Program dks fdlh izdkj dk dksbZ Argument Pass ugha dj jgs gSaA ge ;gka ;fn Arguments Pass Hkh djrs gSa] rks Hkh HelloWorld Program dks ;s irk ugha gksrk gS] fd Supply fd, tkus okys Command Line Arguments ds lkFk D;k izfØ;k djuh gSA
ge ,sls tkok Programs fy[k ldrs gSa tks Command Line ij iznku fd, x, Arguments
dks Use dj ldrk gS vkSj Arguments ds vk/kkj ij fofHkUu izdkj ds Output iznku dj ldrk gSA bls le>us ds fy, main() Method ds Structure dks nsf[k, %
Java in Hindi
ge ns[k ldrs gSa fd main() Method esa args dks ,d Strings ds Array izdkj dk Declare
fd;k x;k gS] tks fd String Objects dks Store dj ldrk gSA Program ds Execution ds
nkSjku ;fn Command Prompt ij dksbZ Hkh Argument iznku fd;k tkrk gS] rks Command
Line ij fn, tkus okys lHkh Argument dk eku args uke ds bl Object esa String Object
ds :i esa Store gks tkrk gSA
main() Method esa ge args Array ds fofHkUu Objects dks Array Elements ds :i esa
Access dj ldrs gSa vkSj fofHkUu izdkj ds Manipulations dj ldrs gSaA mnkgj.k ds fy, eku yks fd ge Command Prompt ij HelloWorld Program dks fuEukuqlkj Interpret djrs gSa%
C:jdk\bin\> java HelloWorld Madhav Raghav Nandlal Madan Gopal
rks args Array ds fofHkUu Elements ds :i esa ;s Objects fuEukuqlkj Store gks tkrs gSa&
Madhav args[0] Raghav args[1] Nandlal args[2] Madan args[3] Gopal args[4]
vc ;fn ge args[3] dks Program esa fdlh izdkj ls Use djuk pkgsa] rks args[3] esa vkus okyk eku Command Prompt ls vk,xk] ftls Handle djus ds fy, ge igys ls gh Codlings
fy[k ldrs gSaA bl Concept ds vk/kkj ij ge fuEukuqlkj ,d Program Develop dj ldrs
gSa%
Program
class CmdLineParameters {
publicstaticvoid main(String args[]) {
int count, i=0; String string; count = args.length;
System.out.println("\nNumber of arguments = " +count+ "\n");
while( i<count) {
string = args[i];
System.out.println( "args[" + i + "] : " + string ); i = i + 1;
}
System.out.println("\n"); }
}
bl Program dks Compile djds tc ge fuEukuqlkj Command Line Arguments ds lkFk
Run djrs gSa] rc gesa vxzkuqlkj ifj.kke izkIr gksrk gS %
Java in Hindi
Output Number of arguments = 7 args[0] : Madhav args[1] : Mohan args[2] : Manmohan args[3] : Madan args[4] : Nandlala args[5] : Balgopal args[6] : Gopalbl Program esa Command Line Arguments dh dqy la[;k dks Kkr djus ds fy, geusa
length Method dks Use fd;k gSA bl Method dk iz;ksx fdlh Hkh Array dh Size Kkr djus ds fy, fd;k tk ldrk gSA
tkok ,d Freeform Language gSA ;kuh tkok dk Program fy[krs le; ;s t:jh ugha gksrk
gS fd tkok ds gj Line ds Codes dks Indent djds ,d gh Form esa j[kk tk,A tkok dks bl
ckr ls dksbZ QdZ ugha iMrk gS fd ge tkok ds Source Codes dks Source File dh fdlh
Line esa dgka ls fy[kuk “kq: djrs gSaA
gkykafd ,slk djus ls gesa gh Program dks Debug djus esa ijs”kkuh gksrh gSA fuEu Statement
dks nsf[k, %
System.out.println(“Balgopal Nandlal”);
bl Statement dks ge Source File esa fuEukuqlkj Hkh fy[k ldrs gSa %
System.out.println (“Balgopal Nandlal”);
blh rjg ls ;fn ge pkgsa] rks blh Statement dks fuEukuqlkj Hkh fy[k ldrs gSa&
System. out. println ( “Balgopal Nandlal” ); Wrapper Classes
geus igys Hkh dgk gS fd tkok ,d Pure Object Oriented Programming Language gSA
;kuh blesa Primary Data Types dks Hkh Objects dh rjg Represent djds fofHkUu izdkj ds dke djus gksrs gSaA gkykafd ge Primary Data Type ds Variables Hkh Create dj ldrs gSa] ysfdu bUgsa fofHkUu izdkj dh Built–In Classes ds lkFk Use djus ds fy, gesa bUgsa Class Type esa Convert djuk iMrk gSA
Java in Hindi
Conversion ds ckn ;s Class dks Represent djrs gSa] ysfdu buds eku esa dksbZ ifjorZu ugha vkrk gS cfYd budks Basic Data Type ls Class Type esa Convert dj fy;k tkrk gS] rkfd fofHkUu izdkj dh Built–In Classes bUgsa vklkuh ls mi;ksx esa ys ldsa vkSj ge bu ij fofHkUu izdkj dh mu Calculations dks Perform dj ldsa] tks dsoy Class ds Objects ds lkFk gh
Perform dh tk ldrh gSaA
lkjka”k esa ge rks ;s dg ldrs gSa fd fofHkUu izdkj ds Basic Data Types dks mudh lEcaf/kr
Wrapper Class }kjk Object esa Convert fd;k tkrk gSA rkfd ge Basic Data Types ds ekuksa dks Hkh mudh Class ds Objects ds :i esa mi;ksx esa ys ldsaA
fofHkUu izdkj ds Basic Data Types ds ekuksa dks Object esa Convert djus ds fy, Number
uke dh ,d Class java.lang uke ds Package esa miyC/k gSA ;s ,d Abstract Class gS ;kuh ge bl Class dk dksbZ Hkh Object Create ugha dj ldrs gSa] cfYd bldh Derived ;k
Subclasses ds Objects Create djrs gSaA
bl Class ls Derive dh xbZ dqy 6 Classes Byte, Short, Integer, Float, Long, Double gSa] tks Øe”k% byte, short, int, float, long, double Basic Data Types dks
Represent djrh gSaA bls ge fuEukuqlkj ,d lkj.kh ds :i esa Represent dj ldrs gSa%
Wrapper Class for Converting Simple Types Simple Data Type Corresponding Wrapper Class
Boolean Boolean Char Character Double Double Float Float Int Integer Long Long
tkok dh bu Wrapper Classes esa fofHkUu izdkj ds Basic Data Type o Objects dks
Handle djus ds fy, dbZ Unique Methods dks Define fd;k x;k gSA buesa ls dqN t:jh o T;knk mi;ksx esa vkus okys Methods o mUgsa mi;ksx esa ysus dk Description vkxs crk;k tk jgk gSA
fdlh Basic Data type ds Variable ;k Constant dks ;fn lEcaf/kr Wrapper Class ds
Object esa Convert djuk gks] rc gesa mu lEcaf/kr Wrapper Classes ds Constructors dks
Use djuk gksrk gSA ;s dke ge fuEukuqlkj Code Statement }kjk dj ldrs gSa%
A. Converting Primary Numbers to Object Numbers Using Constructor Methods
Constructor Calling Performed Conversion Action
Integer IntVal = new Integer( i ); Conversion from int Data Type to Integer Object Float FloatVal = new Float( f ); Conversion from float Data Type to Float Object Double DoubleVal = new Double( d ); Conversion from double Data Type to Double Object Long LongVal = new Long( l ); Conversion from long Data Type to Long Object
Java in Hindi
bl Table esa i, f, d o l Øe”k% int, float, double o long izdkj ds Basic Data Type ds
Variables gSa] ftUgsa muds Corresponding Class ds Object esa Convert fd;k tk jgk gSA ,d ckj fdlh Basic Data Type ds eku dks lEcaf/kr Object esa Convert djus ds fy, fofHkUu izdkj ds Operations Perform djus ds ckn ;fn gesa ml Object dks fQj ls lEcaf/kr Basic Data Type esa Convert djuk gks] rks gesa Wrapper Classes ds fuEu typeValue()
Methods dks Call djuk gksrk gS] tgka type ml Type dks Represent djrk gS] ftl Basic Data Type esa Object ds eku dks Convert djuk gSA
dbZ ckj ,slh t:jr gksrh gS fd gekjs ikl Primary Data Type ds Numerical eku gksrs gSa] ysfdu mUgsa ,d String dh rjg Use djuk gksrk gSA fdlh Numerical eku dks String dh rjg Use djus ds fy, gesa ml Numerical eku dks igys String izdkj ds Representation
esa Convert djuk gksrk gSA fdlh Basic Data Type ds eku dks String Representation ds :i esa Convert djus ds fy, gesa Wrapper Class ds fuEu Methods dks Use djuk gksrk gS%
blh izdkj ls dbZ ckj gesa ,slh t:jr gksrh gS fd gesa fdlh eku dks nwljs eku ls Calculate
djds u;k eku Generate djuk gksrk gS] ysfdu gekjs ikl tks Numerical eku gksrk gS] og
String Format esa gksrk gS] ftl ij fdlh Hkh izdkj ds Numerical Operation dks Directly Perform ugha fd;k tk ldrk gSA
bl fLFkfr esa igys gesa eku ds String Representation dks Wrapper Class Object
Representation esa Convert djuk gksrk gS vkSj mlds ckn ml Object Representation dks
Basic Data Type esa Convert djds eku ds lkFk Calculation Perform djuk gksrk gSA
String Representation dks Wrapper Object esa Convert djus ds fy, gesa fuEu lkj.kh ds vuqlkj dke djuk gksrk gSA
B. Converting Object Numbers to Basic Numbers Using typeValue() Methods
Method Calling Performed Conversion Action
int i = IntObj.intValue(); Conversion from Integer Object to int Data Type float f = FloatObj.floatValue(); Conversion from Float Object to float Data Type double d = DoubleObj.doubleValue(); Conversion from Double Object to double Data Type long l = LongObj.longValue(); Conversion from Long Object to long Data Type
C. Converting Basic Numbers to Strings Using String() Methods
Method Calling Performed Conversion Action
str = Integer.toString( i ); Conversion from int Data Type to String Object str = Float.toString( f ); Conversion from float Data Type to String Object str = Double.toString( d ); Conversion from double Data Type to String Object str = Long.toString( l ); Conversion from long Data Type to String Object
D. Converting String to Numerical Objects Using Static Method ValueOf()
Method Calling Performed Conversion Action
DoubleObj = Double.valueOf( str ); Conversion from String Object to double Data Type FloatObj = Float.valueOf( str ); Conversion from String Object to float Data Type
Java in Hindi
fdlh String Representation dks Numerical Object esa Convert djus ds ckn ml
Numerical Representation dks fQj ls Basic Data Type esa Convert fd;k tk ldrk gSA
Numerical Strings ekuksa dks Parsing Methods dk iz;ksx djds Directly Primary ;k Basic Data Type ds ekuksa esa Convert fd;k tk ldrk gSA Parsing Methods dsoy nks gh gSa] tks fd fdlh Integer ;k Long izdkj ds String Representation dks Directly Integer ;k Long
izdkj ds Basic Data Type dk eku Return dj nsrk gSA
;fn parseInt() o parseLong() Methods esa Pass fd, tkus okys str String Object esa
Integer eku ds vykok dksbZ eku gks] rks ;s Methods ,d NumberFormatException
Throw djrs gSaA blfy, bUgsa try Block esa Use djuk pkfg, vkSj bl Exception dks
Handle djus ds fy, ,d catch Block Hkh fy[kuk pkfg,] vU;Fkk str esa Integer ds vykok dksbZ nwljk eku gksus ij Program Crash ;k Terminate gks tkrk gSA
Program
// File Name: AdditionApplet.java
import java.awt.*;
import java.applet.*;
publicclass AdditionApplet extends Applet {
TextField textField1; TextField textField2; publicvoid init() {
textField1 = new TextField(5); textField2 = new TextField(5); add(textField1);
add(textField2); textField1.setText("0"); textField2.setText("0"); }
publicvoid paint(Graphics g) {
int value1 = 0, value2 = 0, sum = 0; String s ;
g.drawString("Type a number in each box.", 10, 20);
E. Converting Numerical Strings to Primary Numbers Using Parsing Method
Method Calling Performed Conversion Action
int i = Integer.parseInt( str ); Conversion from String Object to int Data Type long i = Long.parseLong( str ); Conversion from String Object to float Data Type