C-and-C++/C4/File-Handling-In-C/English-timed
From Script | Spoken-Tutorial
Time | Narration |
00:01 | Welcome to the spoken-tutorial on files in C . |
00:05 | In this tutorial we will learn: |
00:08 | How to open a file. |
00:10 | How to read data from a file. |
00:12 | How to write data into a file. |
00:15 | Few examples. |
00:17 | To record this tutorial, I am using |
00:20 | Ubuntu Operating System version 11.10, |
00:24 | gcc Compiler version 4.6.1. |
00:28 | Let us start with the introduction to files. |
00:31 | File is a collection of data. |
00:34 | It can be a database, a program, a letter or anything. |
00:39 | We can create a file and access it using C. |
00:44 | Now let us see an example on file handling in C. |
00:48 | I have a written program. |
00:50 | Let's take a look Note that our file name is file.c |
00:55 | In this program we will create a file and write data into it. |
01:01 | Let me explain the code now. |
01:03 | This is our header file. |
01:05 | This is our main() function. |
01:07 | To define a file variable we use the type FILE. |
01:12 | The FILE variable is defined under the header stdio.h. |
01:19 | *fp is a pointer to the FILE variable. |
01:22 | It will store all the information about the file , |
01:26 | like its name, status and current information. |
01:31 | Let us go back to our slides. |
01:33 | Now we will see the syntax to open a file. |
01:37 | Here, the fopen() function opens a stream. |
01:42 | Then it links the file with the stream. |
01:44 | file name is the name of the file that we want to open or create. |
01:49 | We can give the path along with the file name. |
01:53 | And We can also give the extension. |
01:56 | Here we can give the mode of the file. |
01:59 | Let us see the types of modes : |
02:02 | "w" - creates file for read and write. |
02:06 | "r" – opens file for reading. |
02:09 | "a" – writing at the end of the file. |
02:12 | Now come back to our program. |
02:15 | Here, we create a Sample.txt file in write mode. |
02:20 | We can see that the path is given. |
02:23 | Our file will be created on the desktop. |
02:27 | Then we will write the statements into the file. |
02:30 | "Welcome to the spoken-tutorial" and |
02:32 | "This is a test example". |
02:34 | fprintf() writes output to the given output stream. |
02:39 | fclose() closes the file associated with the stream. |
02:43 | And this is our return statement. |
02:46 | Now click on Save. |
02:48 | Let us execute the program. |
02:50 | Open the terminal window by pressing Ctrl, Alt and T keys simultaneously on your keyboard. |
02:59 | To compile, type gcc space file dot c space hyphen o space file |
03:06 | Press Enter To execute, type dot slash file (./file). |
03:11 | Press Enter. |
03:13 | We see the file is executed. |
03:15 | Now we will check it out. |
03:17 | Let us open the Home folder. |
03:20 | Click on the Home folder option. |
03:22 | Now click on the Desktop option. |
03:25 | Here is our sample.txt file. |
03:29 | This shows that our file is successfully created. |
03:32 | Now let us open. |
03:34 | Double click on the file. |
03:36 | We can see the messages here. |
03:39 | Welcome to the Spoken Tutorial. |
03:41 | This is a test example. |
03:44 | This is how we create a file and write data into it. |
03:48 | Now we will see how to read data from a file. |
03:52 | I have already made the program. |
03:54 | I will open it. |
03:56 | In this program, we will read data from our sample.txt file and print the data on the console. |
04:03 | Let me explain the code now. |
04:05 | This is our header file. |
04:08 | This is our main() function. |
04:10 | Here, a file variable and a pointer to the file variable is defined. |
04:15 | Then we have declared a character variable c. |
04:19 | Here, we open the file Sample.txt in read mode. |
04:24 | The output is stored in fp. |
04:27 | Then we check the condition- |
04:29 | "If fp is equal to NULL ". |
04:32 | If the condition is true then we print the message: |
04:36 | "File doesn't exist." |
04:38 | Else, it will check for another condition- |
04:41 | While c is not equal to EOF. |
04:46 | Here, EOF is the end of file. |
04:49 | It denotes the end of input. |
04:52 | It is a condition where no more data can be read from a data source. |
04:57 | If the condition is true then it will display the characters from Sample.txt file, on the console. |
05:06 | Here, getc returns a character from a specified file or stream. |
05:12 | Now, it will return a character from our Sample.txt file. |
05:17 | putchar is used to display a character on the console. |
05:22 | Then it will store the characters in variable c. |
05:25 | Here we close the file. |
05:28 | And this is our return statement. |
05:30 | Now click on Save. |
05:32 | Let us execute the program. |
05:35 | Come back to the terminal. |
05:37 | To compile, type gcc space readfile dot c space hyphen o space read |
05:45 | Now press Enter . |
05:47 | To execute, type ./read (dot slash read). |
05:52 | The output is displayed as: |
05:54 | Welcome to the Spoken-Tutorial. |
05:56 | This is a test example. |
05:59 | This brings us to the end of this tutorial. |
06:01 | Come back to our slides. |
06:03 | Let us summarize .In this tutorial we learnt: |
06:06 | File handling, |
06:08 | To write data into a file. |
06:10 | eg. fp = fopen(“Sample.txt”, “w”); |
06:17 | To read data from a file. eg. fp = fopen(“Sample.txt”, “r”); |
06:25 | As an assignment- Write a program to create a file TEST. |
06:30 | Write your name and address in the file TEST. |
06:33 | Then display it on the console using C Program. |
06:37 | Watch the video available at the link shown below. |
06:40 | It summarizes the Spoken Tutorial project. |
06:43 | If you do not have good bandwidth, you can download and watch it. |
06:47 | The Spoken Tutorial Project Team: |
06:50 | Conducts workshops using spoken tutorials. |
06:53 | Gives certificates to those who pass an online test. |
06:57 | For more details, please write to, contact@spoken-tutorial.org. |
07:03 | Spoken Tutorial Project is a part of Talk to a Teacher project. |
07:07 | It is supported by the National Mission on Education through ICT, MHRD, Government of India. |
07:14 | More information on this Mission is available at the link shown below. |
07:18 | This is Ashwini Patil from IIT Bombay, signing off. |
07:22 | Thank You for joining. |