Does it mean that every program must have a constructor or the program won't run or can give error??

Question

So if we don't provide a constructor, java creates a default constructor. Also Java being object oriented.. Does it mean we have to have a constructor default or otherwise
.??

Answer 1

Yes if you dont put a constructor into your class the compiler will put a default constructor there for you.

A defaut contructor looks like a no-arg constructor but they are diffrent from one another.

theres 3 types.

Default : Class(){};

No-arg. : Class(){Some code};

parameterized : Class(int i, int j){};

Answer 2

Miss Gayatri Palkar
If we not create a constructor .
Compiler create a default constructor..
The question is why it create default constructor
The reason is

-constructor provide default value of data member
And second
-it reutrn the corrent object refference id.
class A
{
int a;
A(A this)
{
this.a=0;
return this;
}
public static void main(String ... A1)
{
A c=new A(address of object);
System.out.println(c.a);
}
}

Now try to understand the defination of this reference variable

This is a reference variable of a class type whic is decleared as a parameter in each instance function available in class