Difference between revisions of "Advanced-C++/C2/Function-Overloading-And-Overriding/English-timed"
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| − | | '''Function overloading'''- | + | | '''Function overloading'''- eg. int add()''' with three different arguments and |
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| − | | Functions with the same '''argument''' and same '''return-type''' and difference between both. | + | | Functions with the same '''argument''' and same '''return-type''' and difference between both.As an assignment. |
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Latest revision as of 14:49, 23 March 2017
| 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. |
