Object and Function in C++.

Passing and Returning Object from Function in C++ Programming

• In C++ programming, objects can be passed to function in similar way as variables and structures.

Procedure to Pass Object to Function

Example to Pass Object to Function

C++ program to add two complex numbers by passing objects to function.

     

  int imag;

    public:

       Complex(): real(0), imag(0) { }

       void Read()

        {

           cout<<"Enter real and imaginary number respectively:"<<endl;

           cin>>real>>imag;

        }

        void Add(Complex comp1,Complex comp2)

        {

            real=comp1.real+comp2.real;

 /* Here, real represents the real data of object c3 because this function is called using code c3.add(c1,c2); */

            imag=comp1.imag+comp2.imag;

 /* Here, imag represents the imag data of object c3 because this function is called using code c3.add(c1,c2); */

        }

        void Display()

        {

            cout<<"Sum="<<real<<"+"<<imag<<"i";

        }

};
int main()
{
    Complex c1,c2,c3;
    c1.Read();
    c2.Read();
    c3.Add(c1,c2);
    c3.Display();
    return 0;
}

Expected Output:-
Enter real and imaginary number respectively:
12
3
Enter real and imaginary number respectively:
2
6
Sum=14+9i


Returning Object from Function

• The syntax and procedure to return object is similar to that of returning structure from function.

Example to Return Object from Function

• This program is the modification of above program displays exactly same output as above. 
• But, in this program, object is return from function to perform this task.

#include <iostream>

using namespace std;

class Complex

{

    private:

       int real;

       int imag;

    public:

       Complex(): real(0), imag(0) { }

       void Read()

        {

           cout<<"Enter real and imaginary number respectively:"<<endl;

           cin>>real>>imag;

        }

        Complex Add(Complex comp2)

        {

            Complex temp;

            temp.real=real+comp2.real;

/* Here, real represents the real data of object c1 because this function is called using code c1.Add(c2) */

            temp.imag=imag+comp2.imag;

/* Here, imag represents the imag data of object c1 because this function is called using code c1.Add(c2) */

            return temp;

        }

        void Display()

        {

            cout<<"Sum="<<real<<"+"<<imag<<"i";

        }

};

int main()

{

Complex c1,c2,c3; 

c1.Read(); 

c2.Read(); 

c3=c1.Add(c2); 

c3.Display(); 

return 0; 

}