Write a Program to allocate memory dynamically for an objects of a given class using class’s constructor

#include<iostream.h>
#include<string.h>
#include<conio.h>
class String
{ 
char *name; 
int length;
public: 
String() 
{ 
length = 0; 
name = new char[length +1]; 
} 
String (char *s) 
{ 
length = strlen(s); 
name= new char[length + 1]; 
strcpy(name, s); 
} 
void display(void) 
{ 
cout<<name<<"\n"; 
} 
void join(String &a, String &b);
};
void String :: join (String &a, String &b)
{ 
length = a.length + b.length;  delete name; 
name = new char [length + 1];
strcpy(name,a.name); 
strcat(name, b.name);
};
int main()
{     
char *first = "Joseph"; 
String name1(first), name2("Louis "), name3("Lagrange"),s1,s2; 
s1.join(name1, name2); 
s2.join(s1, name3); 
name1.display(); 
name2.display(); 
name3.display(); 
s1.display(); 
s2.display();   
return 0;
}