Advanced-C++/C2/Function-Overloading-And-Overriding/English-timed

From Script | Spoken-Tutorial
Revision as of 14:49, 23 March 2017 by Pratik kamble (Talk | contribs)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search
Time Narration
00:01 Welcome to the spoken tutorial on Function Overloading and Overriding in C++.
00:09 In this tutorial, we will learn:
00:11 Function Overloading Function Overriding.
00:14 We will do this with the help of examples.
00:18 To record this tutorial, I am using:
00:21 Ubuntu OS version 11.10
00:26 g++ compiler version 4.6.1
00:30 Let us start with an introduction to function overloading.
00:34 Function Overloading means two or more functions can have same name.
00:41 The number of arguments and the data-type of the arguments will be different.
00:47 When a function is called, it is selected based on the argument list.
00:53 Let us look at an example.
00:56 I have already typed the code on the editor.
00:59 In this program, we will perform addition operations.
01:03 Note that our file name is overload.cpp.
01:08 Let me explain the code now.
01:10 This is our header file as iostream.
01:13 Here we are using the std namespace.
01:17 Then we have add() function defined as int.
01:21 In this, we have passed three arguments.
01:24 Int a, int b and int c.
01:28 Then we perform addition of three numbers and we return the value.
01:33 Here we overload the function add().
01:36 It is declared as float.
01:38 We have passed two arguments float d and float e.
01:44 Then we perform the addition operation on two numbers.
01:48 This is our main() function.
01:50 In function main(), we declare the add() function with different arguments.
01:56 Then we declare the variables.
01:58 Here we accept integer values from the user.
02:03 Then we call the function add() with three arguments
02:07 and store the result in variable sum.
02:09 Here we print the result.
02:12 Now, here we accept floating point numbers from the user.
02:17 Then we call the add() function with two arguments.
02:21 And here we print the sum.
02:23 This is our return statement.
02:26 Now, let us execute the program.
02:29 Open the terminal window by pressing Ctrl, Alt and T keys simultaneously on your keyboard.
02:38 To execute, type: g++ space overload dot cpp space hyphen o space over
02:49 press Enter.
02:51 Type: dot slash over
02:53 press Enter.
02:55 It is displayed- Enter three integers
02:58 I will enter 10, 25 and 48.
03:04 The output is displayed as: Sum of integers is 83
03:09 Now we see- Enter two floating point numbers
03:13 I will enter as: 4.5 and 8.9
03:17 press Enter.
03:19 The output is displayed as: "Sum of floating point numbers is 13.4" .
03:25 Now we will see function overriding.
03:29 Let us switch back to our slides.
03:31 Redefining a base class function in the derived class.
03:36 The derived class function overrides the base class function.
03:40 But the arguments passed are same.
03:44 And the return-type is also same.
03:47 Let us see an example.
03:49 Here is an example on function Overriding.
03:53 Note that our file name is override.cpp.
03:57 Let us go through the code.
04:00 This is our header file as iostream.
04:03 Here we are using the std namespace.
04:06 Then we have class arithmetic.
04:09 In this, we have declared integer variables as as protected.
04:14 Then we have function values() declared as public.
04:18 In this, we have passed two arguments- int x and int y.
04:23 Then we stored the values in a and b.
04:26 Here we have virtual function as operations().
04:30 In this, we add the two numbers and print the sum.
04:34 Here we close the class.
04:37 Now we have class Subtract as derived class.
04:41 This inherits the base class arithmetic.
04:45 In this, we calculate the difference of two numbers and we print the difference.
04:50 Now we have another derived class as Multiply.
04:54 This also inherits base class arithmetic.
04:57 In this, we calculate the product of two numbers and display the product.
05:03 Then we have class Divide . This also inherits the base class arithmetic.
05:09 In this, we calculate the division of two numbers and we display the division.
05:15 Note that the return-type of the function is same and the arguments passed are also same.
05:23 This is our main() function.
05:26 In this, we create an object of class arithmetic as p.
05:31 arith is the pointer to the class arithmetic.
05:35 Then we have subt object of class Subtract.
05:39 mult object of class Multiply.
05:42 And divd object of class Divide.
05:46 Now here, p is set to the address of arith.
05:50 Then we pass arguments as 30 and 12 in function values.
05:56 Now we call the function operations().
05:59 This will perform the addition operation.
06:02 Here we set subt to the address of arith.
06:07 And we pass 42 and 5 as arguments.
06:11 Again we call function operations().
06:14 This will perform subtraction of two numbers.
06:18 Now, here we set mult to the address of arith.
06:22 And we pass 6 and 5 as arguments.
06:26 We call the function operations().
06:29 This will perform the multiplication of two numbers.
06:33 At last, we set divd to the address of arith and we pass 6 and 3 as arguments.
06:41 Now we call the operations() function.
06:44 This will perform the division of two numbers.
06:48 And this is our return statement.
06:50 Let us execute the program. Switch back to the terminal.
06:54 Type: g++ space override dot cpp space hyphen o space over2
07:04 press Enter.
07:06 Type: dot slash over2
07:09 press Enter.
07:11 The output is displayed as:
07:13 Addition of two numbers is 42
07:16 Difference of two numbers is 37
07:19 Product of two numbers is 30 and Division of two numbers is 2
07:25 Let us switch back to our slides.
07:27 Let us see the difference of overloading and overriding.
07:31 Overloading can occur without inheritance.
07:35 Overriding occurs when one class is inherited from another.
07:41 In overloading, the arguments and the return-type must differ.
07:46 In overriding, the arguments and the return-type must be same.
07:51 In overloading, the function name is same.
07:55 But it behaves differently depending on the arguments passed to them.
08:01 In overriding, the function name is same.
08:05 Derived class function can perform different operations from the base class.
08:11 Let us summarize:
08:13 In this tutorial, we learnt:
08:15 Function overloading- eg. int add() with three different arguments and
08:21 float add() with two different arguments.
08:24 Then Function Overriding-
08:26 eg. virtual int operations() and int operations()
08:31 Functions with the same argument and same return-type and difference between both.As an assignment.
08:39 Write a program that will calculate the area of rectangle, square and circle
08:46 using function overloading.
08:48 Watch the video available at the link shown below.
08:52 It summarizes the Spoken-Tutorial project.
08:55 If you do not have good bandwidth, you can download and watch it.
08:59 The Spoken Tutorial Project team:
09:02 Conducts workshops using spoken tutorials.
09:05 Gives certificates to those who pass an online test.
09:09 For more details, please write to:
09:12 contact@spoken-tutorial.org
09:16 Spoken Tutorial Project is a part of the "Talk to a Teacher" project.
09:20 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
09:27 More information on this mission is available at the link shown below.
09:32 This is Ashwini Patil from IIT Bombay, signing off.
09:36 Thank You for joining.

Contributors and Content Editors

Gaurav, PoojaMoolya, Pratik kamble, Ranjana, Sandhya.np14