Classes, Objects, and Methods

Class Syntax

"class" keyword use cheskoni classes ni create chestham java lo.

class ClassName{
// variables
// Methods
// objects
}

Variables Syntax ni previous articles lo discuss chesnam, go and check.

Methods

C language lo manam functions antam kadha, similarly in java manam Methods antam.

They define some behaviour or perform some task.

Methods Syntax

returnType FunctionName(datatype1 var1, datatype2 var2){
// body
}

returnType: Manam oka task or operation ni perform chesna tharvatha return chese value a datatype ni specify chesthado, dani manam return type antam.

void: we do not return any value.

int: Integer value return chestham.

String: String value return chestham.

Function can have 0 to n parameters or arguments.

Objects

Objects Syntax:

As we discussed oka specific class lo data ni access cheyali ante, we need create object.

ClassName ObjName = new ClassName();

"new" keyword use chesthe ah specific object memory lo create chesthunam ani ardam.

Epudu, Objects are main thing, objects use cheskoni verey class data ni access cheskuntam.

objName.OtherClassData -> (.) dot operator is used

Example:

class Student{  
// 1st manam variables ni create cheskutunam
 int rollno;  
 String name;  

//Methods which does not return any value
 void insertRecord(int r, String n){  
  rollno=r;  
  name=n;  
 }  
 void displayInformation(){
    System.out.println(rollno+" "+name);
 }  
}  
// Execution starts from main program
class TestStudent4{  
 public static void main(String args[]){  
// Ekada manam student class kosam 2 students ni create chesthum (Objects)
  Student s1=new Student();  
  Student s2=new Student();
// using (.) dot operator manam Student class lo methods ni access cheskutunam 
  s1.insertRecord(111,"Karan");  
  s2.insertRecord(222,"Aryan");  

  s1.displayInformation();  
  s2.displayInformation();  
 }  
}

OUTPUT

111 Karan

222 Aryan

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stack memory stores only variables of data address, actual data is stored in heap memory.

We have some specific keywords in OOP

static, this, super and some access modifiers which we will discuss in further articles.