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Array of objects initialization with constructors in C++

Here, we will learn how to initialize array of objects using constructors in C++?

In this program, we will define a class and declare array of objects, declare object (array of objects) will be initialized through the constructor.

Here, we are going to define a class named person with two members name and age. These members will be initialized through constructors (default and parameterized).

Program to initialize array of objects in C++ using constructors

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

class person {
private:
    string name;
    int age;

public:
    // default constructor
    person()
    {
        name = "N/A";
        age = 0;
    }

    // parameterized constructor with 
    // default argument
    person(string name, int age = 18)
    {
        this->name = name;
        this->age = age;
    }

    // function to display values
    void display()
    {
        cout << name << "\t" << age << endl;
    }
};

int main()
{
    //array of class objects declaration
    person per[4] = { person("ABC"), person("PQR"), person("XYZ", 30), person() };

    per[0].display();
    per[1].display();
    per[2].display();
    per[3].display();

    return 0;
}

Output

    ABC		18
    PQR		18
    XYZ		30
    N/A		0

Explanation

In the statement person per[4]={"ABC",person("PQR"),person("XYZ",30)};, there are 4 objects and only three initializer values "ABC" - Here, parameterized constructur will call, "ABC" will be assigned into name and age will be default value that is 18.

person("PQR") - Here, parameterized constructur will call, "PQR" will be assigned into name and age will be default value that is 18.

person("XYZ",30) - Here, parameterized constructur will call, "XYZ" will be assigned into name 30 will be assigned into age.

DEFAULT Constructor - Last object p[3] wil be initialized using default constructor, the values of name will be "N/A" and age will be 0.