What is Constructor overloading, Examples and purpose of constructor overloading in C++, OOP

What is Constructor overloading? Give Examples and purpose of constructor overloading in C++ and OOP?

What is Constructor overloading?

Different constructors with the same name is called constructor overloading.

The constructor must obey one or both of the following rules.

All constructors with the same name have a different number of parameters.
- For example numbers_sum(int n1, int n2) and another constructor as numbers_sum(int n1, int n2, int n3) is legal.
All constructors with the same name and have the same number of parameters but of different data types is also legal.
- numbers_sum(int n1, int n2) and another constructor as numbers_sum(float n1, float n2).

Examples of legal and illegal constructor overloading

numbers_sum(int n1, int n2) and numbers_sum(double n1, double n2) is legal in constructor overloading.
.
numbers_sum(int n1, int n2) and numbers_sum(int n1, double n2) is legal in constructor overloading.
numbers_sum(int n1, int n2) and numbers_sum(double n1, int n2) is legal in constructor overloading.
numbers_sum(int n1, int n2) and numbers_sum(int n1, int n2) is illegal in constructor overloading.
numbers_sum(double n1, double n2) and numbers_sum(double n1, double n2) is illegal in constructor overloading.
numbers_sum(int n1) and numbers_sum(int n1, int n2) is legal in constructor overloading.
numbers_sum(int n1, int n2) and numbers_sum(int n1) is legal in constructor overloading.

Example of constructor overloading

Example of constructor overloading with a different number of parameters and constructors with the same name.

#include<iostream>
using namespace std;
class numbers_sum
{
public:
numbers_sum(int n1, int n2)
{
cout<<"sum of 2 numbers is = "<<endl<<n1+n2<<endl;
}
numbers_sum(int n1, int n2, int n3)
{
cout<<"sum of 3 numbers is = "<<endl<<n1+n2+n3<<endl;
}
};
int main()
{
numbers_sum a(3,4);
numbers_sum b(5,5,2);
}

#include<iostream>

using namespace std;

class numbers_sum

{

public:

numbers_sum(int n1, int n2)

{

cout<<"sum of 2 numbers is = "<<endl<<n1+n2<<endl;

}

numbers_sum(int n1, int n2, int n3)

{

cout<<"sum of 3 numbers is = "<<endl<<n1+n2+n3<<endl;

}

};

int main()

{

numbers_sum a(3,4);

numbers_sum b(5,5,2);

}

Output

Sum of two numbers is =
7
the sum of three numbers is =
12

Example of constructors with the same name and have the same number of parameters but of different data types.

#include<iostream>
using namespace std;
class numbers_sum
{
public:
numbers_sum(int n1, int n2)
{
cout<<"sum of 2 numbers is = "<<endl<<n1+n2<<endl;
}
numbers_sum(double n1, double n2)
{
cout<<"sum of 2 numbers is = "<<endl<<n1+n2<<endl;
}
};
int main()
{
numbers_sum a(3,4);
numbers_sum b(1.5,2.5);
}

#include<iostream>

using namespace std;

class numbers_sum

{

public:

numbers_sum(int n1, int n2)

{

cout<<"sum of 2 numbers is = "<<endl<<n1+n2<<endl;

}

numbers_sum(double n1, double n2)

{

cout<<"sum of 2 numbers is = "<<endl<<n1+n2<<endl;

}

};

int main()

{

numbers_sum a(3,4);

numbers_sum b(1.5,2.5);

}

Output

Sum of two numbers is =

the sum of three numbers is =

Another Example of Constructor Overloading In C++

/*  Constructor Overloading In C++
    https://t4tutorials.com
*/
#include<iostream>
#include<conio.h>
using namespace std;
class Example {
    // Variable Declaration
    int n1, n2;
public:
    //Constructor wuithout Argument
    Example() {
        // Assign Values In Constructor
        n1 = 3;
        n2 = 7;
        cout << "\nIm Constructor";
    }
    //Constructor with Argument
    Example(int x, int y) {
        // Assign Values In Constructor
        n1 = x;
        n2 = y;
        cout << "\nI am Constructor";
    }
    void Display() {
        cout << "\nValues :" << n1 << "\t" <<"+"<< n2;
        cout<<"="<<n1+n2;
    }
};
int main() {
    Example Object(33, 7);
    Example Object2;
    // Constructor invoked.
    Object.Display();
    Object2.Display();
    // Wait For Output Screen
    getch();
    return 0;
}

/* Constructor Overloading In C++

https://t4tutorials.com

#include<iostream>

#include<conio.h>

using namespace std;

class Example {

// Variable Declaration

int n1, n2;

public:

//Constructor wuithout Argument

Example() {

// Assign Values In Constructor

n1 = 3;

n2 = 7;

cout << "\nIm Constructor";

}

//Constructor with Argument

Example(int x, int y) {

// Assign Values In Constructor

n1 = x;

n2 = y;

cout << "\nI am Constructor";

}

void Display() {

cout << "\nValues :" << n1 << "\t" <<"+"<< n2;

cout<<"="<<n1+n2;

}

};

int main() {

Example Object(33, 7);

Example Object2;

// Constructor invoked.

Object.Display();

Object2.Display();

// Wait For Output Screen

getch();

return

}

Output

I am Constructor

Im Constructor

Values :33 +7=40

Values :3 +7=10

Constructor Outside the Class

The Syntax for Constructor Outside the Class

class class_name {
public:
//Constructor declaration
class_name();
//… other Variables & Functions
}
// Constructor definition outside Class
class_name::class_name() {
// Constructor code
}

Program of Constructor Outside the Class

/*  Constructor Outside the Class
https://t4tutorials.com
*/
#include <iostream>
#include<conio.h>
using namespace std;
// Class Declaration

class T4Tutorials {
   int a, b;
   //Access - Specifier
public:
   //Constructor declaration
   T4Tutorials();
   //Member Functions for display 'a & b' Values.

   void Display() {
      cout << "Values :" << a << "\t" << b;
   }
};
// Constructor definition outside Class
T4Tutorials::T4Tutorials() {
   // Assign Values In Constructor
   a = 33;
   b = 7;
   cout << "This is Constructor Outside the Class\n";
}
int main() {

   // Object Creation For Class
   T4Tutorials Object;
   // Constructor invoked.
   Object.Display();
   // Wait For Output Screen
   getch();
   return 0;
}

/* Constructor Outside the Class

https://t4tutorials.com

#include <iostream>

#include<conio.h>

using namespace std;

// Class Declaration

class T4Tutorials {

int a, b;

//Access - Specifier

public:

//Constructor declaration

T4Tutorials();

//Member Functions for display 'a & b' Values.

void Display() {

cout << "Values :" << a << "\t" << b;

}

};

// Constructor definition outside Class

T4Tutorials::T4Tutorials() {

// Assign Values In Constructor

a = 33;

b = 7;

cout << "This is Constructor Outside the Class\n";

}

int main() {

// Object Creation For Class

T4Tutorials Object;

// Constructor invoked.

Object.Display();

// Wait For Output Screen

getch();

return 0;

}

Copy Constructor

A copy constructor is just like a normal Constructor with the parameters, but the parameter is the same class object. The Copy constructor is helpful to initialize an object using another object of the same class.

C++ Program of Copy Constructor

/*  Of Copy Constructor Overloading In C++
    https://T4Tutorials.com             */

#include<iostream>
#include<conio.h>

using namespace std;

class T4Tutorials {
   // Member Variable Declaration
   int a, b;
public:

   //Normal Constructor with Argument

   T4Tutorials(int x, int y) {
      // Assign Values In Constructor
      a = x;
      b = y;
      cout << "\n I am Constructor";
   }

   //Copy Constructor with Obj Argument

   T4Tutorials(const T4Tutorials& obj) {
      // Assign Values In Constructor
      a = obj.a;
      b = obj.b;
      cout << "\nI am Copy Constructor";
   }

   void Display() {
      cout << "\nValues :" << a << "\t" << b;
   }
};

int main() {
   //Normal Constructor Invoked
   T4Tutorials Object(10, 20);

   //Copy Constructor Invoked - Method 1
   T4Tutorials Object2(Object);

   //Copy Constructor Invoked - Method 2
   T4Tutorials Object3 = Object;

   Object.Display();
   Object2.Display();
   Object3.Display();
   return 0;
}

/* Of Copy Constructor Overloading In C++

https://T4Tutorials.com */

#include<iostream>

#include<conio.h>

using namespace std;

class T4Tutorials {

// Member Variable Declaration

int a, b;

public:

//Normal Constructor with Argument

T4Tutorials(int x, int y) {

// Assign Values In Constructor

a = x;

b = y;

cout << "\n I am Constructor";

}

//Copy Constructor with Obj Argument

T4Tutorials(const T4Tutorials& obj) {

// Assign Values In Constructor

a = obj.a;

b = obj.b;

cout << "\nI am Copy Constructor";

}

void Display() {

cout << "\nValues :" << a << "\t" << b;

}

};

int main() {

//Normal Constructor Invoked

T4Tutorials Object(10, 20);

//Copy Constructor Invoked - Method 1

T4Tutorials Object2(Object);

//Copy Constructor Invoked - Method 2

T4Tutorials Object3 = Object;

Object.Display();

Object2.Display();

Object3.Display();

return 0;

}

What are the advantages of constructor overloading?

It acts as compile-time polymorphism.
Objects can be constructed in different ways.
Helpful when we are programming the big problem because it is easy to remember the constructor name if many constructors are with the same name.

Constructor Destructor C++ Exercise with Solution

Write a program in C++ to convert a decimal number into binary without using an array and using the constructor and destructor. – Solution
Write a program in C++ to convert a decimal number into binary without using an array by using the constructor overloading. – Solution
Write a c++ program to find out the sum of an A.P. series using constructor and destructor. – Solution
Write a c++ program to find out the sum of an A.P. series by using the constructor overloading. – Solution
Write a program in C++ to print Floyd’s Triangle by using the constructor destructor. – Solution
Write C++ Program to display the cube of the number upto a given integer using Destructor. – Solution
Write C++ Program to display the cube of the number upto a given integer using constructor overloading. – Solution
Write a C++ program to find Strong Numbers within a range of numbers using constructor C++. – Solution
Write a C++ program to find Strong Numbers within a range of numbers Using destructor in C++. – Solution
Write a C++ program to find Strong Numbers within a range of numbers by using constructor overloading in C++. – Solution
Let’s see the C++ program to show the Sum of n number of odd natural numbers by using the Constructor Overloading. – Solution
Let’s see the Sum of n number of an odd natural number using constructor and destructor in C++. Solution
Sum of the series Using Constructor Overloading in C++. Solution
Sum of the series Using Destructor in C++. Solution
Sum of the series Using Constructor in C++. Solution
Write a program in C++ to find the sum of the series using the constructor overloading. Solution
Write a program in C++ to find the sum of the series by using the constructor and destructor. Solution
Write a program in C++ to print a pattern of right angle triangle with a number that will repeat a number in the row by using the constructor and destructor. Solution
Write a program in C++ to print a pattern of right angle triangle with a number that will repeat a number in the row by using the constructor overloading. Solution
Write a C++ program to display Pascal’s triangle using the Constructor Destructor. Solution
Write a C++ program to display Pascal’s triangle using the Constructor Overloading. Solution
C++ program of Constructor Destructor to display a pattern for a number of rows. Solution
C++ program Constructor Destructor program to print the hollow square or rectangle star pattern. Solution.
C++ program to display the diamond-like pattern using the Constructor Destructor. Solution
C++ program to display the diamond-like pattern using the Constructor Overloading. Solution
Write a program in C++ to convert an octal number into binary using constructor and destructor. Solution
Write a program in C++ to convert an octal number into binary using constructor overloading. Solution
C++ Program with constructor destructor to display the pattern like pyramid. Solution
Write a C++ Program to display the reverse of a number using the constructor destructor. Solution
Write a C++ Program to display the reverse of a number using the constructor overloading. Solution
Write a C++ program to print rhombus star pattern of Number of rows using constructor overloading and destructor. Solution
Write a program in C++ to Check Whether a Number can be Express as Sum of Two Prime Numbers using constructor and destructor. Solution
Write a program in C++ to find the sum of the series using constructor destructor. Solution
Write a C++ program of binary to octal conversion with Constructor with constructor. Solution
Write the Octal to Decimal number program in C++ using constructor overloading and destructor? Solution
Write a program in C++ to make such a pattern like a pyramid with a number which will repeat the number in the same row using constructor overloading and destructor. Solution
Write a C++ program to find the number and sum of all integer between 100 and 200 which are divisible by 9 with constructor destructor. Solution
Constructor Fibonacci series C++ Program. Solution

Test Your Understandings

1. Constructor overloading means different function name same number of parameters and with same data types? YES / NO

Answer - Click Here:

2. int sum(int a, int b) and another constructor is sum(int a, int b). Here constructor is overloaded? YES / NO

Answer - Click Here:

3. int sum(int a, int b) and another constructor is sum(int a, int b, int c). Here constructor is overloaded? YES / NO

Answer - Click Here:

YES

Topic Covered

What is Constructor overloading, Examples and purpose of constructor overloading in C++, OOP.

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