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Dr. Charles Simonyi is the Father of Modern Microsoft Excel                                           JavaScript was originally developed by Brendan Eich of Netscape under the name Mocha, later LiveScript, and finally renamed to JavaScript.                                           The word "Biology" is firstly used by Lamarck and Treviranus                                           Hippocrates (460-370 bc) is known as father of medicine.                                           Galene, 130-200 is known as father of Experimental Physology                                           Aristotle (384-322 BC) is known as Father of Zoology because he wrote the construction and behavior of different animals in his book "Historia animalium"                                           Theophrastus(370-285 BC) is known as father of Botany because he wrote about 500 different plants in his book "Historia Plantarum".                                           John Resig is known as Father of Jquery -                                          HTML is a markup language which is use to design web pages. It was invented in 1990 by Tim Berners-Lee.                                                                The Google was founded by Larry Page and Sergey Brin.                                                                Rasmus Lerdorf was the original creator of PHP. It was first released in 1995.                                                               Facebook was founded by Mark Zuckerberg                                                               Bjarne Stroustrup, creator of C++.                                                                Dennis Ritchie creator of C                                                                                                                              James Gosling, also known as the "Father of Java"                                          At 11.44%, Bihar is India's fastest growing state                                          Father of HTML -Tim Berners Lee                                          orkut was created by Orkut Büyükkökten, a Turkish software engineer                    Photoshop: It came about after Thomas Knoll, a PhD student at the University of Michigan created a program to display grayscale images on a monochrome monitor which at the time was called 'Display'.

file Handling in c


Creating a file and output some data

In order to create files we have to learn about File I/O i.e. how to write data into a file and how to read data from a file. We will start this section with an example of writing data to a file. We begin as before with the include statement for stdio.h, then define some variables for use in the example including a rather strange looking new type.
/* Program to create a file and write some data the file */
#include <stdio.h>
#include <stdio.h>
main( )
{
     FILE *fp;
     char stuff[25];
     int index;
     fp = fopen("TENLINES.TXT","w"); /* open for writing */
     strcpy(stuff,"This is an example line.");
     for (index = 1; index <= 10; index++)
      fprintf(fp,"%s Line number %d\n", stuff, index);
     fclose(fp); /* close the file before ending program */
}
The type FILE is used for a file variable and is defined in the stdio.h file. It is used to define a file pointer for use in file operations. Before we can write to a file, we must open it. What this really means is that we must tell the system that we want to write to a file and what the file name is. We do this with the fopen() function illustrated in the first line of the program. The file pointer, fp in our case, points to the file and two arguments are required in the parentheses, the file name first, followed by the file type.
The file name is any valid DOS file name, and can be expressed in upper or lower case letters, or even mixed if you so desire. It is enclosed in double quotes. For this example we have chosen the name TENLINES.TXT. This file should not exist on your disk at this time. If you have a file with this name, you should change its name or move it because when we execute this program, its contents will be erased. If you don’t have a file by this name, that is good because we will create one and put some data into it. You are permitted to include a directory with the file name.The directory must, of course, be a valid directory otherwise an error will occur. Also, because of the way C handles literal strings, the directory separation character ‘\’ must be written twice. For example, if the file is to be stored in the \PROJECTS sub directory then the file name should be entered as “\\PROJECTS\\TENLINES.TXT”. The second parameter is the file attribute and can be any of three letters, r, w, or a, and must be lower case.

Reading (r)

When an r is used, the file is opened for reading, a w is used to indicate a file to be used for writing, and an a indicates that you desire to append additional data to the data already in an existing file. Most C compilers have other file attributes available; check your Reference Manual for details. Using the r indicates that the file is assumed to be a text file. Opening a file for reading requires that the file already exist. If it does not exist, the file pointer will be set to NULL and can be checked by the program.
Here is a small program that reads a file and display its contents on screen.
/* Program to display the contents of a file on screen */
#include <stdio.h>
void main()
{
   FILE *fopen(), *fp;
   int c;
   fp = fopen("prog.c","r");
   c = getc(fp) ;
   while (c!= EOF)
   {
     putchar(c);
  c = getc(fp);
   }
   fclose(fp);
}

Writing (w)

When a file is opened for writing, it will be created if it does not already exist and it will be reset if it does, resulting in the deletion of any data already there. Using the w indicates that the file is assumed to be a text file.
Here is the program to create a file and write some data into the file.
#include <stdio.h>
int main()
{
 FILE *fp;
 file = fopen("file.txt","w");
 /*Create a file and add text*/
 fprintf(fp,"%s","This is just an example :)"); /*writes data to the file*/
 fclose(fp); /*done!*/
 return 0;
}

Appending (a)

When a file is opened for appending, it will be created if it does not already exist and it will be initially empty. If it does exist, the data input point will be positioned at the end of the present data so that any new data will be added to any data that already exists in the file. Using the a indicates that the file is assumed to be a text file.
Here is a program that will add text to a file which already exists and there is some text in the file.
#include <stdio.h>
int main()
{
    FILE *fp
    file = fopen("file.txt","a");
    fprintf(fp,"%s","This is just an example :)"); /*append some text*/
    fclose(fp);
    return 0;
}

Outputting to the file

The job of actually outputting to the file is nearly identical to the outputting we have already done to the standard output device. The only real differences are the new function names and the addition of the file pointer as one of the function arguments. In the example program, fprintf replaces our familiar printf function name, and the file pointer defined earlier is the first argument within the parentheses. The remainder of the statement looks like, and in fact is identical to, the printf statement.

Closing a file

To close a file you simply use the function fclose with the file pointer in the parentheses. Actually, in this simple program, it is not necessary to close the file because the system will close all open files before returning to DOS, but it is good programming practice for you to close all files in spite of the fact that they will be closed automatically, because that would act as a reminder to you of what files are open at the end of each program.
You can open a file for writing, close it, and reopen it for reading, then close it, and open it again for appending, etc. Each time you open it, you could use the same file pointer, or you could use a different one. The file pointer is simply a tool that you use to point to a file and you decide what file it will point to. Compile and run this program. When you run it, you will not get any output to the monitor because it doesn’t generate any. After running it, look at your directory for a file named TENLINES.TXT and type it; that is where your output will be. Compare the output with that specified in the program; they should agree! Do not erase the file named TENLINES.TXT yet; we will use it in
some of the other examples in this section.
Reading from a text file
Now for our first program that reads from a file. This program begins with the familiar include, some data definitions, and the file opening statement which should require no explanation except for the fact that an r is used here because we want to read it.
#include <stdio.h>
   main( )
   {
     FILE *fp;
     char c;
     funny = fopen("TENLINES.TXT", "r");
     if (fp == NULL)
  printf("File doesn't exist\n");
     else {
      do {
       c = getc(fp); /* get one character from the file
       */
         putchar(c); /* display it on the monitor
       */
       } while (c != EOF); /* repeat until EOF (end of file)
     */
     }
    fclose(fp);
   }
In this program we check to see that the file exists, and if it does, we execute the main body of the program. If it doesn’t, we print a message and quit. If the file does not exist, the system will set the pointer equal to NULL which we can test. The main body of the program is one do while loop in which a single character is read from the file and output to the monitor until an EOF (end of file) is detected from the input file. The file is then closed and the program is terminated. At this point, we have the potential for one of the most common and most perplexing problems of programming in C. The variable returned from the getc function is a character, so we can use a char variable for this purpose. There is a problem that could develop here if we happened to use an unsigned char however, because C usually returns a minus one for an EOF – which an unsigned char type variable is not
capable of containing. An unsigned char type variable can only have the values of zero to 255, so it will return a 255 for a minus one in C. This is a very frustrating problem to try to find. The program can never find the EOF and will therefore never terminate the loop. This is easy to prevent: always have a char or int type variable for use in returning an EOF. There is another problem with this program but we will worry about it when we get to the next program and solve it with the one following that.
After you compile and run this program and are satisfied with the results, it would be a good exercise to change the name of TENLINES.TXT and run the program again to see that the NULL test actually works as stated. Be sure to change the name back because we are still not finished with TENLINES.TXT.

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