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

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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.
00:12 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 v. 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 pass 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 And this is our return statement
02:26 Now let us execute the program
02:29 Open the terminal 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 filename is override.cpp.
03:57 Let us go through the code.
04:00 This is our header file as iostream
04:03 Here we have the std namespace.
04:06 Then we have class arithmetic.
04:09 In this we have declared integer variablesas as protected.
04:14 Then we have function values declared as public.
04:18 In these we have passed two arguments int x and int y.
04:23 Then we stored the value 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 then 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 Now 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 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 pass arguments as 6 and 5 as argument
06:26 We call function operations.
06:29 This will perform multiplication of two numbers.
06:33 Atlast we set divd to the address of arith And we pass 6 and 3 as arguments.
06:41 Now we call operations functions
06:44 This will perform division of two numbers.
06:48 And this is our return statement.
06:50 Let us execute the program. Switch back to our 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 occurs 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 learnt
08:15 Function overloading.
08:16 eg. int add with three different arguments and
08:21 float add with two different arguments.
08:24 Function Overriding.
08:26 eg. virtual int operations () and int operations ()
08:31 functions with the same argument and same return type and


08:36 Difference between both.
08:38 As an assignment
08:39 Write a program that will calculate the area of rectangle, square and circle
08:46 Using function overloading.


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09:32 This is Ashwini Patil from IIT Bombay signing off
09:36 Thank You for joining.

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