Program:

#include <iostream>
#include <string.h>
using namespace std;

class person{
	private:
		char name[30];
		int age;
	
	public:
		//default constructor
		person(){
			strcpy(name,"None");
			age = 0;
		}
		//parameterized constructor
		person(char n[], int a){
			strcpy(name, n);
			age = a;
		}
		//copy constructor
		person(person &p){
			strcpy(name, p.name);
			age =p.age;
		}
		//function to display person details
		void print(void){
			cout<<name<<" is "<<age<<" years old."<<endl;
		}
};

//Main function
int main(){
	//creating objects
	person p1; //default constructor will be called
	person p2("Amit Shukla",21); //parameterized constructor will be called
	person p3(p2); //copy constructor will be called
	
	//printing
	cout<<"object p1..."<<endl;
	p1.print();
	cout<<"object p2..."<<endl;
	p2.print();	
	cout<<"object p3..."<<endl;
	p3.print();	
	
	return 0;
}

Output

object p1...
None is 0 years old.
object p2...
Amit Shukla is 21 years old.
object p3...
Amit Shukla is 21 years old.