The document explains constructors in programming, specifically in C++, highlighting their purpose, types, and usage. It details three types of constructors: non-parameterized, parameterized, and copy constructors, with code examples for each. Constructors are special methods used to initialize object data at the time of creation and do not have a return type.

1. Constructors

2.  Constructor is a special method which is invoked
automatically at the time of object creation. It is used to
initialize the data members of new objects generally.
 Constructors have the same name as class or structure.
 Constructors don’t have a return type. (Not even void)
 Constructors are only called once, at object creation.

3. Types of constructor
 There can be three types of constructors .
 1. Non-Parameterized constructor :A constructor which
has no argument is known as non-parameterized
constructor(or no-argument constructor). It is invoked at
the time of creating an object.

4. Code example
 #include <iostream>
 using namespace std;
 class Student {
 private:
 string name;
 int age;
 string course;
 public:
 // Non-parameterized constructor
 Student() {
 name = “Ali";
 age = 0;
 course = “2nd";
 }
 // Function to display student details
 void displayDetails() {
 cout << "Name: " << name << endl;
 cout << "Age: " << age << endl;
 cout << "Course: " << course << endl;
 }
 };
 int main() {
 // Create an object of Student using non-parameterized constructor
 Student student1;
 // Display default student details
 student1.displayDetails();
 return 0;
 }

5.  2. Parameterized constructor : Constructor which has
parameters is called a parameterized constructor. It is
used to provide
 different values to distinct objects.

6.  #include <iostream>
 using namespace std;
 class Student {
 private:
 string name;
 int age;
 string course;
 public:
 // Parameterized constructor
 Student(string studentName, int studentAge, string studentCourse) {
 name = studentName;
 age = studentAge;
 course = studentCourse;
 }
 // Function to display student details
 void displayDetails() {
 cout << "Name: " << name << endl;
 cout << "Age: " << age << endl;
 cout << "Course: " << course << endl;
 }
 };
 int main() {
 // Creating an object of Student using the parameterized constructor
 Student student1("Alice", 20, "Computer Science");

 // Display student details
 student1.displayDetails();
 return 0;
 }

7.  Copy Constructor
 A copy constructor is a member function that initializes
an object using another object of the same class.

8.  #include <iostream>
 using namespace std;
 class Student {
 private:
 string name;
 int age;
 string course;
 public:
 // Parameterized constructor
 Student(string studentName, int studentAge, string studentCourse) {
 name = studentName;
 age = studentAge;
 course = studentCourse;
 }
 // Copy constructor
 Student(const Student &source) {
 name = source.name;
 age = source.age;
 course = source.course;
 cout << "Copy constructor called!" << endl;
 }
 // Function to display student details
 void displayDetails() {
 cout << "Name: " << name << endl;
 cout << "Age: " << age << endl;
 cout << "Course: " << course << endl;
 }
 };

9.  int main() {
 // Create an object of Student using parameterized constructor
 Student student1("Bob", 22, "Mathematics");

 // Create a new object using the copy constructor
 Student student2 = student1; // Copy constructor is called here

 // Display details of both students
 cout << "Details of student1:" << endl;
 student1.displayDetails();
 cout << "nDetails of student2 (copy of student1):" << endl;
 student2.displayDetails();
 return 0;
 }