Dynamic Constructor in C++

mahendragohil.gohil@gmail.com

Allocation of memory to objects at the time of their construction is known as dynamic constructors of objects. The memory is allocated with the help of new operator.

The constructors can also be used to allocate memory while creating objects dynamically. This will enable the system to allocate the right amount of memory for each object when the objects are not of the same size, thus resulting in the saving of memory.

Dynamic memory allocation is always refers the use of new operator. Dynamic memory allocation is directly connected with the pointer data type.

Example:

#include<iostream.h>
#include<string.h> 
class string
{
     char *name;
     int length;
public:
     string ( )
     {
        length=0;
        name= new char [length+1];    /* one extra for \0 */
     }
    string( char *s) //constructor 2
    {
       length=strlen(s);
       name=new char [length+1];
       strcpy(name,s);
    }
    void display(void)
    {
       cout<<name<<endl;
    }
    void join(string &a , string &b)
    {
        length=a.length + b.length;
        delete name;
        name=new char[length+l];    /* dynamic allocation */
        strcpy(name,a.name);
        strcat(name,b.name);
     }
};
int main( )
{
char * first = “Jay” ;
string name1(first),name2(“Lalji”),naine3( “Maharaj”),sl,s2;
sl.join(name1,name2);
s2.join(s1,name3);
namel.display( );
name2.display( );
name3.display( );
s1.display( );
s2.display( );
}
output:
Jay
Lalji
Maharaj
Jay Lalji
Jay Lalji Maharaj

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