0
None, zero. Example: new MyClass(); //and public classMyClass{} no constructor defined inside of MyClass
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What is the difference between default constructor and parameterized constructor?
A default constructor is one that has no parameters (C++ also calls constructors with all default parameters a default constructor), while a parameterized constructor is one that has at least one parameter without a default value. Default constructors can be provided by the compiler if no other constructors are defined for that class or any class the class inherits from, while parameterized constructors must always be defined by the developer.
What is the method of constructor overloading in c plus plus?
Constructor overloading, just like any function's overloading, is where more than one configuration of parameters exists for the function. Based on the number and type of the parameters, different versions of the function can be resolved by the linker. This is typically used in the constructor as the default constructor (no parameters), the copy constructor (one reference parameter of the same type as the class), and the conversion constructor (any other combination of parameters).
Default constructor in java?
If you don't type a constructor into your class code, a default constructor will be automatically generated by the compiler. The default constructor is ALWAYS a no-arg constructor. (Obviously the compiler has no clue what all arguments you might want for your class. So it takes the safe way out with a no argument constructor) A no-arg constructor is not necessarily the default (i.e., compiler-supplied) constructor, although the default constructor is always a no-arg constructor. The default constructor is the one the compiler provides! While the default constructor is always a no-arg constructor, you're free to put in your own no-arg constructor.
What is the need of parameterized constructor?
Parametrized constructors are used to increase the flexibility of a class, allowing objects to be instantiated and initialised in more ways than is provided by the default and copy constructors alone. If you define any parametrized constructor, including a copy constructor, you will lose the default constructor generated by the compiler and must declare your own if you need one. The default constructor can also be parametrized, but each parameter must include a default value in the declaration, so that it can be called without any parameters.
What is a constructoris it mandatory to use constructor in a class?
You always should define default constructor for your class. You must also define a copy constructor for your class if there are any pointers in the class. While it is not mandatory, failure to provide a default constructor can result in bad behavior, and failure to provide a copy constructor when you have pointers in the class will result in bad behavior. For example, without a default constructor, the compiler will not fully initialize the attributes of the class. It will initialize the virtual function table, and call base class constructors, but that is all - the attributes could be random garbage. For another example, without a copy constructor, the compiler will generate one that simply makes a bit wise copy of the attributes. If these attributes contain pointers, then you have two pointers to the same object, not necessarily a good thing, especially if one of them get "deleted".
What is a default parameterized constructor?
There is no such thing as a default parameterized constructor. The default constructor is always the 'no-arg' constructor and does not take any parameters or arguments as input
What is the difference between default constructor and parameterized constructor?
A default constructor is one that has no parameters (C++ also calls constructors with all default parameters a default constructor), while a parameterized constructor is one that has at least one parameter without a default value. Default constructors can be provided by the compiler if no other constructors are defined for that class or any class the class inherits from, while parameterized constructors must always be defined by the developer.
What is the method of constructor overloading in c plus plus?
Constructor overloading, just like any function's overloading, is where more than one configuration of parameters exists for the function. Based on the number and type of the parameters, different versions of the function can be resolved by the linker. This is typically used in the constructor as the default constructor (no parameters), the copy constructor (one reference parameter of the same type as the class), and the conversion constructor (any other combination of parameters).
Default constructor in java?
If you don't type a constructor into your class code, a default constructor will be automatically generated by the compiler. The default constructor is ALWAYS a no-arg constructor. (Obviously the compiler has no clue what all arguments you might want for your class. So it takes the safe way out with a no argument constructor) A no-arg constructor is not necessarily the default (i.e., compiler-supplied) constructor, although the default constructor is always a no-arg constructor. The default constructor is the one the compiler provides! While the default constructor is always a no-arg constructor, you're free to put in your own no-arg constructor.
What is the need of parameterized constructor?
Parametrized constructors are used to increase the flexibility of a class, allowing objects to be instantiated and initialised in more ways than is provided by the default and copy constructors alone. If you define any parametrized constructor, including a copy constructor, you will lose the default constructor generated by the compiler and must declare your own if you need one. The default constructor can also be parametrized, but each parameter must include a default value in the declaration, so that it can be called without any parameters.
What is a constructoris it mandatory to use constructor in a class?
You always should define default constructor for your class. You must also define a copy constructor for your class if there are any pointers in the class. While it is not mandatory, failure to provide a default constructor can result in bad behavior, and failure to provide a copy constructor when you have pointers in the class will result in bad behavior. For example, without a default constructor, the compiler will not fully initialize the attributes of the class. It will initialize the virtual function table, and call base class constructors, but that is all - the attributes could be random garbage. For another example, without a copy constructor, the compiler will generate one that simply makes a bit wise copy of the attributes. If these attributes contain pointers, then you have two pointers to the same object, not necessarily a good thing, especially if one of them get "deleted".
How is the default constructor equivalent to a constructor having default arguments?
Any constructor that can be invoked without explicitly passing any arguments is a default constructor. Note that there can be only one default constructor so there can only be one constructor where all arguments have default values or one constructor that has no arguments, but not both. A constructor where all arguments have default values is a useful means of combining two or more constructors into a single default constructor, thus reducing verbosity and code duplication.
Why you require constructor in cpp?
Constructors are not a requirement of CPP. A default constructor and copy constructor are automatically generated by the compiler for every class you create when no constructors are declared. The only time you need to declare a constructor is when you wish to override the default behaviour of the generated constructors, to ensure the class is correctly initialised. When any constructor is declared, the default constructor is no longer generated by the compiler -- you must define your own default constructor (one that has no parameters, or where all the parameters have default values). The copy constructor is always generated for you regardless of how many other constructors you declare. But if the class contains pointers to allocated memory that is "owned" by the class then you must override the generated copy constructor with your own copy constructor. This is to ensure the memory is deep copied (the generated copy constructor only performs a shallow, member-wise copy of the members). Otherwise two objects of the same class will end up pointing at the same memory, which would be disastrous if either one were to be deleted. The other instance would be automatically invalidated because it would point to memory that was released by the other instance's destructor.
How do you get a default constructor?
The default constructor is an empty (only call the super constructor) with no parameters constructor inserted by the java compiler when you don't define a constructor in your class. If you write something like this: public class NoConstructorClass{ //no constructor goes here } Then you get something like this: public class NoConstructorClass{ public NoConstructorClass(){ // Default constructor that you didn't write super(); } }
When a object is passed to a function as argument why it is not generating an error if the parameterized constructor is defined and not the default constructor?
default constructor is used only when the programmer does not use a constructor to initialize objects. Once the programmer defines a constructor then the default constructor is no longer used
Why are constructors dynamic rather than static by default?
Because the JVM decides are run time which constructor to invoke depending on the parameters passed to it
What is another name of default constructor?
No-Arg Constructor
