Arrays of Objects

An array of objects stores multiple objects of the same class type.

Example idea:

Student students[3];

This creates three Student objects.

Important Constructor Rule

If you create a fixed-size array like this:

Student students[3];

the class must have a default constructor, because each object is created without arguments.

Complete Example

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

class Student {
private:
    string name;
    int marks;

public:
    Student() : name("Unknown"), marks(0) {}

    Student(string studentName, int studentMarks)
        : name(studentName), marks(studentMarks) {}

    void display() const {
        cout << name << ": " << marks << endl;
    }
};

int main() {
    Student students[3] = {
        Student("Riaz", 85),
        Student("Nadia", 90),
        Student("Karim", 78)
    };

    for (const Student& student : students) {
        student.display();
    }

    return 0;
}

Output:

Riaz: 85
Nadia: 90
Karim: 78

Modern Alternative: vector

In modern C++, std::vector is often preferred because it can grow dynamically.

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

class Book {
private:
    string title;

public:
    explicit Book(string bookTitle) : title(bookTitle) {}

    void display() const {
        cout << title << endl;
    }
};

int main() {
    vector<Book> books;

    books.emplace_back("OOP in C++");
    books.emplace_back("Data Structures");

    for (const Book& book : books) {
        book.display();
    }

    return 0;
}

Viva Answer

An array of objects stores multiple objects of the same class. If a fixed-size object array is created without initializer values, the class needs a default constructor. In modern C++, std::vector is often preferred for dynamic size.

Quick Check

1. Why does Student students[3]; need a default constructor?
2. What is the advantage of vector over a fixed array?
3. How can we loop through an array of objects safely?