How to pass and return object from C++ Functions?

In C++ programming, we can pass objects to a function in the same way as passing built-in data types.

Example 1: C++ Pass Objects to Function

// C++ program to calculate the average marks of two students

#include <iostream>
using namespace std;

class Student {

   public:
    double marks;

    // constructor to initialize marks
    Student(double m)
      : marks{m} {
    }
};

// function that has objects as parameters
double average_marks(Student s1, Student s2) {

    // return the average of marks of s1 and s2 
    return (s1.marks + s2.marks)/2 ;
}

int main() {
    Student student1(88.0), student2(56.0);

  // pass the objects as arguments
   cout << "Average Marks = " << average_marks(student1, student2) << "\n";

    return 0;
}

Output

Average Marks = 72

Here, we have passed two Student objects student1 and student2 as arguments to the calculateAverage() function.

Example 2: C++ Return Object from a Function

#include <iostream>
using namespace std;

class Student {
   public:
    double marks1, marks2;
};

// function that returns object of Student
Student createStudent() {
    Student student;

    // Initialize member variables of Student
    student.marks1 = 96.5;
    student.marks2 = 75.0;

    // print member variables of Student
    cout << "Marks 1 = " << student.marks1 << endl;
    cout << "Marks 2 = " << student.marks2 << endl;

    return student;
}

int main() {
    Student student1;

    // Call function
    student1 = createStudent();

    return 0;
}

Output

Marks1 = 96.5
Marks2 = 75

In this program, we have created a function createStudent() that returns an object of Student class.

We have called createStudent() from the main() method.

// Call function
student1 = createStudent();

Here, we are storing the object returned by the createStudent() method in the student1.