What is constructor in Cpp with example?

• Same name as class name
• No return type
• Implicitly called just after object creation
• Used to initialize data members (initial object state)

Note:- Constructor shoudn’t be called explicitly after initialization, consider update or set function for any further changes.
 
Example on constructor in Cpp.
 

const double CALL_RATE = 1.0;

class Customer {
  int m_id;
  std::string m_name;
  std::string m_phone;
  double m_balance;

public:
  Customer(int id, std::string name, std::string phone, double balance) {
    m_id = id;
    m_name = name;
    m_phone = phone;
    m_balance = balance;
  }
  Customer(int id, std::string name, std::string phone) {
    m_id = id;
    m_name = name;
    m_phone = phone;
    m_balance = 500;
  }
  void makeCall(int nmins) { m_balance -= nmins * CALL_RATE; }
  void recharge(double amount) { m_balance += amount; }
  double getBalance() { return m_balance; }
  void display() {
     // print m_id,m_name,m_phone, m_balance
  }
};
int main() {
  Customer c1(1001, "Scott", "9845012345", 500.0);
  c1.makeCall(10);
  c1.recharge(100);
  c1.display();

  Customer c2; //??

  Customer c3(1002, "Meyers", "9845012345");
  c3.display();
  return 0;
};