Can we use parameterized constructor without default constructor?

You must create a default constructor in your class in order to use it. Reason for this – By creating a parameterized constructor, you are restricting that, instance can be created only through parameterized constructor.

What if there is no default constructor?

5 Answers. If you define a class without any constructor, the compiler will synthesize a constructor for you (and that will be a default constructor — i.e., one that doesn’t require any arguments).

What happens if there is no default constructor in Java?

If it does not find any constructor in your superclass without parameters, it will give you a compiler error. Similary if super(parameters) is called, the compiler will expect your superclass to have a constructor with parameters(number and type of parameters should match).

Can we have parameterized constructor without default constructor in C++?

As per my understanding, if we specify parametrized constructor then compiler wont create default one for us and we need default constructor only if we are creating object without any arguments( If i have declared a parametrized constructor and created an object by passing parameters then compiler wont give error) .

What happens if we define parameterized constructor only?

If there is any one parametrized Constructor present in a class, Default Constructor will not be added at Compile time. So if your program has any constructor containing parameters and no default constructor is specified then you will not be able to create object of that class using Default constructor.

What is constructor explain the difference between default and parameterized constructor?

Default Constructor vs Parametrized Constructor

Is it always necessary to provide a default constructor for a class Why or why not?

Note that if we write any constructor in the class, default constructor by the compiler will not be provided and also, note that default constructor is an empty constructor. You can read default functions of a class in c++ provided by compiler .

What happens if there is no constructor defined in a class *?

If we don’t define a constructor in a class, then the compiler creates default constructor(with no arguments) for the class. And if we write a constructor with arguments or no-arguments then the compiler does not create a default constructor.

Why is default constructor important?

If not Java compiler provides a no-argument, default constructor on your behalf. This is a constructor initializes the variables of the class with their respective default values (i.e. null for objects, 0.0 for float and double, false for boolean, 0 for byte, short, int and, long).

Why do we need a default constructor in C++?

Compiler defined default constructor is required to do certain initialization of class internals. It will not touch the data members or plain old data types (aggregates like an array, structures, etc…). However, the compiler generates code for default constructor based on the situation.

What is the difference between parameterized and non parameterized constructor?

The default constructor is a constructor that the compiler automatically generates in the absence of any programmer-defined constructors. Conversely, the parameterized constructor is a constructor that the programmer creates with one or more parameters to initialize the instance variables of a class.

Can we have both default constructor and parameterized constructor in the same class?

We can have any number of Parameterized Constructor in our class. In this example, I have implemented four constructors: one is default constructor and other three are parameterized. During object creation the parameters we pass, determine which constructor should get invoked for object initialization.

What is the purpose of a parameterized constructor?

If a class does not have a constructor, a default constructor is automatically generated and default values are used to initialize the object fields. When you add a parameterized constructor you are basically saying this class needs these particular parameters in order to be properly initialized.

Why we can not create an object with default constructor?

If we have only a parameterized constructor in class then why we can not create the object with default constructor? as before adding the parameterized constructor, there was no default constructor present in class! still, an instance of lass can be created by default constructor.

What happens when default constructor is overloaded with parameterized constructor?

When default constructor is overloaded with parameterized constructor, It is necessary to have a default constructor in code when you create object using default constructor instead of parameterized constructor.

Why can’t I write a constructor with no parameters?

You don’t have a constructor without parameters, so you can’t write new student (). Note that if you don’t write any constructors at all, the compiler will automatically make a constructor for you, without parameters, but as soon as you write one constructor, this doesn’t happen.