oops

 /// What is OOP's

/// Class
/// Object
/// Constructor : Default,  Parameterized,  Named

// main() {
//   var obj = new class1(); //Creating the class Object to Access the class properties
//   var obj = class1();      //Another way to creating the class object
//   obj.fun1();             //Accessing the class Function through Object
//   print(obj.name);        //Accessing the class variable through Object
// }
// class class1 {
//   var name = "Vishal";  //Creating the class Variable
//   fun1() {              //Creating the class Function
//     print("Hello");
//   }
// }

/// Use the variable in the function and Assign value to that variable through class Object
// main() {
//   var obj1 = new class2();
//   obj1.name = "Vishal";
//   obj1.fun2();
//
//   var obj2 = new class2();
//   obj2.name = "Amit";
//   obj2.fun2();
// }
// class class2 {
//   var name;
//   fun2() {
//     print("Hello " + name);
//   }
// }

/// Constructor
/// Default Constructor
// Constructor is a special method of Dart class which is automatically called
// when the object is created. The constructor is like a function with/without parameter
// but it doesn’t have a return type. Default, parameterized, and named constructors
// are known as “generative constructors” since they purely generate an instance.

// main() {
//   var obj3 = new class3();
//   obj3.fun3();
// }
// class class3 {
//   class3() {
//     print("Hello");
//   }
//   fun3() {
//     print("I am Vishal");
//   }
// }

/// Parameterized Constructor
// main() {
//   var obj4 = new class4("Amit");
//   obj4.fun4();
// }
// class class4 {
//   var name; //OR  var _name;
//   ///1st way
//   class4(name) {
//     this.name = name; //OR  _name = name;
//   }
//   ///2nd Way (Short Version of Parameterized Constructor)
//   //class4(this.name);
//
//   // "this" keyword is used to indicate that passing the value of parameter "name" into the class Variable "name" and
//   // calling the class Variable "name" in the function fun4().The "this" keyword refers to the current instance.
//   // Use this only when there is a name conflict
//   // The this keyword is used to refer the current class object.
//   // It indicates the current instance of the class, methods, or constructor.
//   // It can be also used to call the current class methods or constructors.
//   // It eliminates the uncertainty between class attributes and the parameter names are the same.
//   //"this" keyword can be used to call instance variable of current class.
//   //"this" can be used to set the values of the instance variable.
//   //"this" can be used to return the current class instance.
//
//   fun4() {
//     print("I am " + name);  //OR  print("I am" + _name);
//   }
// }

/// Named Constructor
/// Implementation
// class_name.constructor_name ( parameters ){
// // Body of Constructor
// }

// main() {
//   //we can keep desired Constructor name in Named Constructor
//   //Default Constructor and Parameterized Constructor can't be used Simultaneously
//   var obj5 = class5.myConstructor("Vishal");  //Object making using Parameterized Constructor
//   obj5.fun5();
// }
// class class5 {
//   var name;
//   class5.myConstructor(name) {
//     //print("hello");
//     this.name = name;
//   }
//   fun5() {
//     print("My Name is " + name);
//   }
// }
main() {
  class6 obj = new class6.myConstructor1("Yogesh", 40);
  class6.myConstructor2(5,5);
  class6.myConstructor3();
  obj.fun6("Ramesh");
}
class class6 {
  class6.myConstructor1(String s, int i) {
    print("hello");
    print("My Father's name is " + s + " and his age is ${i}" );
  }
  class6.myConstructor2(int a, int b) {
    print("Sum of a and b is : ${a + b}");
  }
  class6.myConstructor3() {
    print("Default Constructor");
  }
  fun6(String r) {
    print("My Name is ${r}, " + r);
  }
}

// main() {
//   demo obj = new demo();
//   obj.demo1(3);
// }
// class demo {
//   demo() {
//     print("One");
//   }
//   demo1(int i) {
//     print("Two");
//   }
// }