0
A parametrised constructor is any constructor that accepts one or more arguments where the first argument has no default value. If all parameters have default values then the constructor is regarded as being a default constructor that is overloaded.
The copy constructor is an example of a parametrised constructor. If you do not define your own, one is generated for you by the compiler, However, the compiler-generated copy constructor performs a member-wise copy. If your class contains member pointers to memory allocations that are owned by the class, this will result in two or more classes owning the same memory, which would prove disastrous when any one instance is destroyed (it will completely invalidate all other instances).
Therefore you must provide your own copy constructor to ensure every instance of the class owns its own allocations, by deep copying the pointers (copying the memory being pointed at rather than just the pointers).
Other than that, there is no requirement to provide any parametrised constructor. You only need to provide parametrised constructors when you want to provide an alternative method of construction.
Note that if you declare any parametrised constructor, including a copy constructor, the compiler does not generate a default constructor for you. If you require one, then you must provide your own. The default constructor may be parametrised provided all parameters are assigned default values.
As an example, consider the following simple class that has a default constructor (as well as a compiler-generated copy constructor):
class simple
{
public:
simple():m_data(0){}
void setdata(const float data){m_data = data;}
void setdata(const int data){m_data = ( float ) data;}
private:
float m_data;
};
When we instantiate this class, the data member is initialised to 0. If we wish to change the data member, we must subsequently call one of the setdata() methods. However, it would be more efficient to set the data member when the class is instantiated. Therefore we should provide a parametrised default constructor:
simple(float data=0):m_data(data){}
We should also provide a parametrised constructor to cater for integers:
simple(int data):m_data(( float ) data){}
Now we no longer need to call setdata() to initialise the class as we can do it all via the constructors.
What else can I help you with?
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.
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
What is mean constructor in java?
A parameterized constructor in java is just a constructor which take some kind of parameter (variable) when is invoked. For example. class MyClass { //this is a normal constructor public MyClass(){ //do something } //this is a parameterized constructor public MyClass(int var){ //do something } //this is another parameterized constructor public MyClass(String var, Integer var2){ //do something } }
What is parameterised constructor?
A parameterized constructor is one that takes multiple arguments/parameters as input. Ex: let us say we want to create multiple constructor for a class Test Public class Test { Public Test() { //code } Public Test(int vals) { //code } Public Test(String val) { //code } }
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(); } }
Constructor and destructor invocation in c?
Not possible in C.
What is the difference between implicit and explicit call of constructor in c plus plus?
An implicit constructor call will always call the default constructor, whereas explicit constructor calls allow to chose the best constructor and passing of arguments into the constructor.
What is a no args constructor?
No args means no arguments. Just like any regular method, a constructor can have zero or more arguments.No args means no arguments. Just like any regular method, a constructor can have zero or more arguments.No args means no arguments. Just like any regular method, a constructor can have zero or more arguments.No args means no arguments. Just like any regular method, a constructor can have zero or more arguments.
What are the steps to add a menu to a frame in advance java?
step 1: create menubar object and set it step 2: create menu objects with parameterized constructor step 3: add menus to menubar
True or False A C plus plus class constructor cannot return a function value?
True - A C++ constructor cannot return a value.
What is conustrutor?
A constructor is a function in C which has the same name of the class. The constructor can be used to initialize some function.
