What are the differences between Constructors and Methods?

Question

Rajanikant Hawaldar · Answer

Constructors Purpose of cunstructor is to create an instance of a class Modifiers cannot be abstract, sealed, native, static, or synchronized No return type, not even void Same name as the class (first letter is capitalized by convention) -- usually a noun 'this' Refers to another constructor in the same class. If used, it must be the first line of the constructor 'base' calls the constructor of the parent class. If used, must be the first line of the constructor Constructors are not inherited Methods Purpose is to group of C# statements Modifiers can be abstract, sealed, native, static, or synchronized Return type is void or a valid return type Any name except the class. 'this' refers to an instance of the owning class. Cannot be used by static methods. 'base' calls an overridden method in the parent class Methods are inherited

Aravind Govindaraj · Answer

A contractor is one who is called automatically while you instantiate the class, however methods we need to call manually. In a real-time scenario, In a new model car/motorbike, while you start an engine, dim lights are auto-on without any manual operation( constructor case). however, if you want to press the horn then we have to do it manually that is called as a method. hope this helps you better

Toufik El Azzaoui · Answer

Constructors are used to initialize the state of the object. Like methods, a constructor also contains a collection of statements that are executed when the object is created. Whenever an object is created using the new() keyword, at least one constructor (it may be the default constructor) is called to assign initial values to the data members of the same class.

Mahesh Chand · Answer

A constructor is a method. A constructor is called and code is executed when a new instance of a type is created. So, you want to put code in a constructor that you want automatically be executed when a new instance is created such as initialization of variables.

Amit Mohanty · Answer

The important difference between constructors and methods is that constructors create and initialize objects that don't exist yet, while methods perform operations on objects that already exist. Constructors can't be called directly; they are called implicitly when the new keyword creates an object. Methods can be called directly on an object that has already been created with new. The definitions of constructors and methods look similar in code. They can take parameters, they can have modifiers (e.g. public ), and they have method bodies in braces. Constructors must be named with the same name as the class name. They can't return anything, even void (the object itself is the implicit return). Methods must be declared to return something, although it can be void.

Sachin Singh · Answer

Constructor initializes the uninialized member variables of a class and are necessary for object creation. When we create an object with new keyword the parameter-less constructor is called that initializes all variables of the class which are not initialized before, to their default values like int to zero and string to null. public class ClassA { public int _x; public ClassA() { } public ClassA(int x) { this._x=x; } } Public Class ClassB { public void Method1() // this is method { ClassA obj = new ClassA(); // default constructor of ClassA is called; ClassA obj = new ClassA(10);// parameter constructor of ClassA is called; } } Methods are like small piece of code which does some action and may or may not retrurn something. for example a piece of code can save data to DB and can return a bool flag indicating sucess or can also be void. public bool Save() { // save to db return true; }

Uday Dodiya · Answer

Constructors are special methods used to initialize objects whereas methods are used to execute certain statements. Following are the important differences between Constructors and Methods. Sr. No. Key Constructors Methods 1 Purpose Constructor is used to create and initialize an Object . Method is used to execute certain statements. 2 Invocation A constructor is invoked implicitly by the System. A method is to be invoked during program code. 3 Invocation A constructor is invoked when new keyword is used to create an object. A method is invoked when it is called. 4 Return type A constructor can not have any return type. A method can have a return type. 5 Object A constructor initializes an object which is not existent. A method can be invoked only on existing object. 6 Name A constructor must have same name as that of the class. A method name can not be same as class name. 7 Inheritance A constructor cannot be inherited by a subclass. A method is inherited by a subclass. Example of Constructor vs Method public class MyClass { int num; MyClass () { this.num = 15; System.out.println(("Constructor invoked. num: " + this.num)); } public void init() { this.num = 10; System.out.println(("Method invoked. num: " + this.num)); } public static void main(String[] args) { MyClass test = new MyClass (); test.init(); } } Output : Constructor invoked. num: 15 Method invoked. num: 10

Brahma Prakash Shukla · Answer

Constructors Methods A Constructor is a block of code that initializes a newly created object. A Method is a collection of statements which returns a value upon its execution. A Constructor can be used to initialize an object. A Method consists of Java code to be executed. A Constructor is invoked implicitly by the system. A Method is invoked by the programmer. A Constructor is invoked when a object is created using the keyword new . A Method is invoked through method calls. A Constructor doesn’t have a return type. A Method must have a return type. A Constructor initializes a object that doesn’t exist. A Method does operations on an already created object. A Constructor’s name must be same as the name of the class. A Method’s name can be anything. A class can have many Constructors but must not have the same parameters. A class can have many methods but must not have the same parameters. A Constructor cannot be inherited by subclasses. A Method can be inherited by subclasses.

Jignesh Kumar · Answer

Hi Anand, There are few major difference among Constructor and Method, Please find as below, Constructor is a special kind of method in the class which gets executed when its object is created . Usually, we put the initialization code in the constructor. Method will not get called when object is created, We have to call method using object name or class name incase it is static method. Constructor doesn't have any return type Method must have return type either void or any other type like int, string, decimal or any complex type. Constructors cannot be declared with the keyword virtual. Method can be declared with the keyword virtual .

Vishal Yelve · Answer

A constructor is a special method that usually has the same name as the class, and we can use it to set the values of the members of an object to either default or user-defined values. Whereas, a method is a programmed procedure that is defined as part of a class and included in any object of that class. These definitions give an idea about the fundamental difference between constructor and method. Return type : To add to this, the constructor has no return type whereas method can return a value or not. Hence, this is another difference between constructor and method. Default : An important difference between constructor and method is that the program will call the default constructor in case the programmer does not write a constructor. However, there are no default methods. Name: A constructor has the same name as the class name while a method can have any name other than keywords. Invocation : One other difference between constructor and method is that the constructors implictly invoke whereas the methods invoke explicitly. Usage : Furthermore, constructor helps to initialize an object whereas a method helps to exhibit the functionality of an object.