constructor overloading in c++

Constructor play an important part in c++. They can initialize the values of a given object to some known values. This is important as constructor will be able to set some values in objects which otherwise may have some garbage values. Most uninitialized value in objects are main cause of the bugs.
But the concept of constructor can allow us to do just anything beside initializing values. Constructor are always called when an object is created. This property of constructor is very useful in situation when you need to perform some task as soon as an object is created.
So constructor is a special function that gets called automatically when an object is created. This function can like any other function do anything (like initializing values).
Overloading Constructor :
This process is very similar to the overloading of simple functions. Since constructor are also function , they can be overloaded like any other functions. This allows user to create many constructor, which can help user to create (and set) objects differently. In most cases objects have data member set to private (so user can't directly change the values of the objects). Different constructor can allow creation of objects with desired type of values.
Method :
Overloading a constructor is very similar to function overloading. Just change the signature (no. of args and type of args) of the constructor.
Overloaded Constructor Usage::
<class name> <objectname>(args);
like Box b; or Box b2(9);

Code:

#include<iostream>

using namespace std;

class box
{
    //data member  are private
    int width,height,length;
    
    public:
    
    box()
    {
        //default constructor 
        //initializes values to 0;
        width=height=length=0;
    }
    box(int k)
    {
        //overloaded constructor with one argument
        //will initialize all 3 data member to value 'k'
        width=height=length=k;
    }
    box(int x,int y,int z)
    {
        //overloaded constructor with 3 argument
        //will initialize data member differently
        width=x;
        height=y;
        length=z;
    }
    void show()
    {
        //function to show these values
        cout<<"\n Width="<<width;
        cout<<"\n Height="<<height;
        cout<<"\n Length="<<length;
    }
    
};

int main()
{
    box b;//using default constructor
    box b2(9);//using 1st overloaded constructor
    box b3(1,2,3);//using 2nd overloaded constructor
    
    b.show();
    b2.show();
    b3.show();
}