UP Board Solutions Class 10 Computer Science Chapter 11 File Operation

File Operation Long Answer Type Questions (8 Marks)

Question 1. What are the data files? Write about their different types. Or Write a short note on ‘Sequential files'. Or Write short notes on ‘Random files' and their application. Or Explain the features of Sequential file.
Answer: Data File: Data file offers a convenient method of storing data sets, since data files can be easily read and updated by program file ('C’ program). Example of Data file is an employee file, which is a collection of related records.
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र 'एम्प्लॉई फाइल' की संरचना को दर्शाता है, जहाँ डेटा को रिकॉर्ड्स (Record 1, Record 2, Record 3, Record n) में व्यवस्थित किया गया है। प्रत्येक रिकॉर्ड में 'नाम', 'पता', और 'वेतन' जैसे 'कॉल्ड फील्ड्स' होते हैं, जो यह बताते हैं कि डेटा कैसे संरचित है। Data files can be categorized in many ways. But we will categorize them only on the basis of mode of accessing. According to this condition, there are following two types of data files:
1. Sequential data files
2. Random data files.
1. Sequential Data Files: The main advantage of this type of file is that records (data) are stored sequentially, one after another, on the storage media which may be a magnetic tape or a disk. These individual data items may be different records or single entities and may comprise numerics or strings or both. If a particular data is of string type, then it must be enclosed within quotation mark.
The main disadvantage of handling the sequential file is that any particular record can be accessed sequentially. For example, if the sixtieth record from the beginning of a sequential file is to accessed, then it has to pass over the preceding fifty-nine records. Thus, it becomes more time-consuming. But if we compare it with a random data file, it is easy to create and handle.
2. Random Data Files: The basic advantage of these files is that any particular record can be accessed directly. For example, if we want to access the sixtieth record, then it can be accessed directly without passing any preceding record. It can be stored on disks only. Thus, this method is quite faster as compared to sequential data files. For this purpose, we use function fseek. This function sets the file position indicator associated with the stream according to the values of the offset and origin. The value of origin may be one of the following:
• 0 - the beginning of a file
• 1 - current position
• 2 - end of the file.
In simple words: Data files store related information, like an employee's details. They are mainly of two types: sequential, where data is accessed in order (like reading a book page by page), and random, where any specific data can be accessed instantly (like jumping to a specific page). Sequential files are easy to handle but slower for specific records, while random files are faster for direct access.

🎯 Exam Tip: When describing file types, ensure you clearly state the advantages and disadvantages of both sequential and random access, including how data is stored and retrieved. Mention `fseek` for random access for full marks.

Question 2. Discuss different file operations of 'C'.
Answer: File Operation: Following are the compulsory steps to operate files:
1. Create file.
2. Merging file i.e., combine records of two or more files into one.
3. Adding records.
4. Deleting records.
5. Update records.
6. Generate reports.
The 'C' language supports different level of file processing according to the environment used.
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र C भाषा में फाइल प्रोसेसिंग के स्तरों को दर्शाता है। इसमें एक 'हाई लेवल' और एक 'लो लेवल' का विभाजन है, जिसमें 'DOS' का उपयोग आमतौर पर फाइल ऑपरेशन में किया जाता है, जो C भाषा के फाइल हैंडलिंग मॉडल को दर्शाता है। The general functions which are supported by 'C' in the file processing are:
• Input functions
• Output functions
Input functions: -getc() -fgetc() -fscanf() -fread()
Output functions: -putc() -fputc() -fprintf() -fwrite()
fopen() is the main function to start the above given functions. To open a file, to create a file, to restart with existing file etc., are the main functions which are performed by it. Syntax: file pointer = fopen(filename, mode); i.e., FILE *fp; fp = fopen(TRY.C”, “r”); fp is a pointer variable, which contains the address of the structure FILE which has been defined in the header file “stdio.h”. fopen() will open a file TRY.C' in 'read* mode, which tells the C compiler that we would be reading the contents of the file, “r” is a string and not a character. Hence, fopen() performs three important tasks when you open the file in “r” mode:
• If the file is present, it loads that file from the disk into memory. If the file is absent, fopen() returns a NULL. This function opens one file at a time.
• It sets up a character pointer which points to the first character of the memory where the file has been modified.
In simple words: 'C' language offers functions for various file operations like creating, merging, adding, deleting, updating records, and generating reports. These operations are managed by functions such as `fopen()` (to open/create files), `fread()`/`fscanf()` (for input), and `fwrite()`/`fprintf()` (for output), allowing programs to interact with files stored on disk.

🎯 Exam Tip: List all six file operations clearly. Mention the key input/output functions and explain the role of `fopen()` with its syntax and a brief description of what it does when opening a file in 'r' mode. This shows a comprehensive understanding.

Question 3. Write about different modes in which a file can be opened.
Answer: File Opening Modes: The tasks performed by fopen() when a file is opened in each of these modes are also mentioned. Character Used for Mode
\( \implies \) Meaning
w
\( \implies \) Create for write
r
\( \implies \) Open for reading
a
\( \implies \) Open for append/create a new file
w+
\( \implies \) Create for read/write
r+
\( \implies \) Open for read/write
a+
\( \implies \) Open for read/write/create new file.
In simple words: Files in 'C' can be opened in various modes using `fopen()`, each dictating what operations are allowed. For example, 'w' creates a new file for writing, 'r' opens an existing file for reading, and 'a' opens for appending. Modes like 'w+', 'r+', and 'a+' allow both reading and writing, with slight differences in how they handle existing or new files.

🎯 Exam Tip: Create a table or a clear list detailing each file opening mode (w, r, a, w+, r+, a+) and its exact purpose (e.g., "Create for write" or "Open for read/write"). Accuracy in describing each mode's functionality is crucial.

Question 4. WAP to copy the contents of one file to another?
Answer: Program:
#include
#include
void main()
{
FILE *fsrc, *ftgt;
char ch;
clrscr();
fsrc = fopen(“tiyl.c”, “r”);
if (fs = = NULL)
{
puts ("Cannot open source file");
exit();
}
ftgt = fopen("tiy2.c”, “w”);
if (ft == NULL)
{
puts ("Cannot open target file");
fclose(fs);
exit();
}
while(1)
{ . ch = fgetc(fsrc);
if (ch = = EOF)
break;
else
fputc(ch, ftgt);
}
fclose(fsrc);
fclose(ftgt);
}
In simple words: This 'C' program copies content from a source file ("tiyl.c") to a target file ("tiy2.c"). It opens both files, reads character by character from the source using `fgetc()`, writes each character to the target using `fputc()`, and continues until the end of the source file (EOF) is reached. It includes error checks for file opening.

🎯 Exam Tip: Pay attention to file pointers (`fsrc`, `ftgt`), file opening modes (`"r"` for source, `“w”` for target), character-by-character copying (`fgetc`, `fputc`), and essential error handling (checking for `NULL` after `fopen()`) and file closing (`fclose()`).

Question 5. Explain fread () and fwrite () functions.
Answer: fread(): This function reads a specified number of equal-sized data items from an input stream into a block, fread returns the number of items (not bytes) actually read on success. Syntax: fread (& name_of_structure, size_of_(structure name), I, file pointer); e.g.,
struct employee
{
char nm[20]; /* 20 bytes */
int age; /* 2 bytes */
};
struct employee Emp;
fread (&Emp, size of (Emp), 1, fp);
Here, the fread function can read 22 bytes of information from the file pointed by file pointer fp. fwrite(): This function appends a specified number of equal-sized data items to an output file. Syntax: fwrite (& struct-name, size of (struct), 1, fp); e.g.,
street address
{
char city [30]; /* 30 bytes */
long in pin; /* 2 bytes */
char country [20]; /* 20 bytes */
};
struct address add;
FILE *fp;
fwrite (& add, size of (add), 1, fp);
In simple words: `fread()` and `fwrite()` are C functions used for binary file I/O, primarily with structures. `fread()` reads blocks of data from a file into memory, while `fwrite()` writes blocks of data from memory to a file. Both functions require the address of the data, its size, the number of items, and the file pointer.

🎯 Exam Tip: Clearly define what `fread()` and `fwrite()` do (read/write blocks of data) and specify their syntax parameters: address of data, size of each item, number of items, and file pointer. Providing code examples for struct usage is highly beneficial.

Question 6. Describe the main features of printf and getchar function.
Answer: printf()
\( \implies \) This function writes formatted data to screen. This function allows to supply the input in a fixed format and to obtain the output in the specified form. The printf () function interprets the contents of the format string. Syntax: Printf ("formatted string”, variables); if needed Example 1. Printf (“Average = % d percentage = % of', avg. per); Here the %d and %f are conversion characters. They tell printf () to print the value of avg as an integer and per as afloat.
getchar(): Using this function any single ASCII character can be inputted in any char type of a variable. This function is available in stdio.h header file so it must be included in the program, in the beginning, using # include declarative. For example,
#include
#include
void main ()
{
char x;
x = getchar();
cout << "you entered" << x;
}
In simple words: `printf()` is used for formatted output to the console, allowing control over how data (like integers or floats) is displayed using format specifiers like `%d` and `%f`. `getchar()` is used to read a single character input from the keyboard, storing it in a character variable. Both functions are fundamental for basic input/output in C.

🎯 Exam Tip: For `printf()`, highlight its role in formatted output, the use of format specifiers, and provide a clear syntax example. For `getchar()`, emphasize its single-character input nature and the necessary header file inclusion (`stdio.h`).

File Operation Short Answer Type Questions (4 Marks)

Question 1. What is stdin and what is stdout?
Answer: In 'C' language, whatever values are given or displayed on a monitor, it can be file handling first stored in a buffer area. The two buffer areas used for this are:
• stdin: It stands for keyboard buffer as it stores the information sent by the keyboard.
• stdout: It stands for standard output buffer, le., monitor of the computer.
In simple words: `stdin` refers to the standard input stream, typically the keyboard, where input data is temporarily stored in a buffer. `stdout` refers to the standard output stream, typically the monitor, where output data is temporarily stored in a buffer before being displayed.

🎯 Exam Tip: Clearly define both `stdin` and `stdout` as standard input and output buffers, respectively, and associate them with their typical hardware (keyboard for `stdin`, monitor for `stdout`).

Question 2. Differentiate fprintf() and fscanf().
Answer: fprintf(): This function sends formatted output to a stream. It accepts a series of arguments, apply to each argument a format specifier contained in the format string * format. This function applies the first format specifier to the first argument, the second specifier to the second argument... till the end of the format. fscanf(): This function is similar to scanf() function. It scans a series of input fields one character at a time. Store the formatted input at an address passed as an argument following * format. This function might stop scanning a particular field before it reaches the normal end-of-field (while space) character, or it might terminate entirely.
In simple words: `fprintf()` writes formatted data to a specified file stream, much like `printf()` writes to the console, using format specifiers. Conversely, `fscanf()` reads formatted data from a specified file stream, similar to how `scanf()` reads from the keyboard, scanning input fields based on format specifiers until a whitespace or end-of-file.

🎯 Exam Tip: Highlight that both `fprintf()` and `fscanf()` are file-stream versions of `printf()` and `scanf()` respectively, dealing with formatted data. Emphasize `fprintf()` for output to a file and `fscanf()` for input from a file, both using format specifiers.

Question 3. What is reading files?
Answer: Reading from files: To read from a file, 'C' provides the following functions: To read data from file, it should exist. fscanf (): This function is used to read data from a file. It is very similar to scanf () function. It scans a series of input fields (one at a time). Syntax: fscanf () file * stream, “format specifiers”, "Variables").
In simple words: Reading files in 'C' means retrieving data stored in a file into a program. Functions like `fscanf()` are used for this, allowing the program to read formatted input from the file, similar to how `scanf()` reads from the keyboard. The file must exist for reading to occur.

🎯 Exam Tip: Explain "reading files" as the process of extracting data from a file. Focus on `fscanf()` as a primary function, its similarity to `scanf()`, and the use of format specifiers and variables to store the read data.

Question 4. What is the closing of the file?
Answer: Closing Files: During a write to a file, the data written is not put on the disk immediately. It is stored in a buffer. When the buffer is full, all its contents are actually written to the disk. The process of emptying the buffer by writing its contents to disk is called flushing the buffer. Losing the file flushes the buffer and releases the space taken by the FILE structure which is returned by fopen. For this fclose () function is used. Syntax: fclose (File * stream (s);
In simple words: Closing a file means saving any buffered data to the disk (flushing the buffer) and releasing the system resources associated with the file, such as the `FILE` structure. The `fclose()` function is used for this essential operation, ensuring data integrity and efficient resource management.

🎯 Exam Tip: Emphasize the two main aspects of file closing: flushing any buffered data to the disk to prevent data loss, and releasing system resources associated with the file. Mention `fclose()` and its syntax as the function used for this purpose.

File Operation Very Short Answer Type Questions (2 Marks)

Question 1. In which type of file, accessing a particular record is faster?
Answer: Random data file.
In simple words: Accessing a specific record is faster in a random data file because it allows direct access to any data location without needing to read through previous records.

🎯 Exam Tip: Remember that "random data file" provides direct access, making it faster for specific record retrieval compared to sequential files.

Question 2. Which statement is used to close a file?
Answer: fclose() statement.
In simple words: The `fclose()` function is used to close a file, ensuring all buffered data is written and resources are freed.

🎯 Exam Tip: Always associate `fclose()` with the action of closing a file in C programming.

Question 3. When data is to be written on a file, in which mode it should be opened?
Answer: 'w' mode (for writing).
In simple words: To write data to a file, it should be opened in 'w' (write) mode; this mode will create a new file or overwrite an existing one.

🎯 Exam Tip: The 'w' mode (write mode) is specifically for writing new content to a file. Be aware that it overwrites existing files.

Question 4. Which statement is used to read the data from a file?
Answer: fread() statement is used to read the data from a file.
In simple words: The `fread()` function is typically used to read blocks of binary data from a file into memory.

🎯 Exam Tip: While `fscanf()` reads formatted data, `fread()` is the function specifically designed for reading raw blocks of data from files, often used with structures.

Question 5. What do you know about ffiush() statement?
Answer: If the given stream has buffered output, fflush writes the output for a stream to the associated file.
In simple words: The `fflush()` statement is used to immediately write any buffered data from an output stream to its associated file, ensuring that the data is not lost if the program terminates unexpectedly.

🎯 Exam Tip: Remember `fflush()`'s main role is to "flush" or write buffered output data to the disk immediately, particularly useful for ensuring data is saved before closing a file or in critical operations.

Question 6. Which is function prints error message corresponding to the last Library routine that produced the error?
Answer: perror ().
In simple words: The `perror()` function prints a descriptive error message to the standard error, explaining the last error encountered by a library routine.

🎯 Exam Tip: `perror()` is key for debugging C programs by providing human-readable error explanations, especially after file operations or other library function calls.

Question 7. Which file pointer position of seeking function seeks from the beginning?
Answer: SEEK SET.
In simple words: `SEEK_SET` is a constant used with file seeking functions like `fseek()` to specify that the file pointer should be set relative to the beginning of the file.

🎯 Exam Tip: `SEEK_SET`, `SEEK_CUR`, and `SEEK_END` are crucial constants for `fseek()` to control the file pointer's position relative to the beginning, current position, or end of the file, respectively.

File Operation Objective Type Questions (1 Marks)

Question 1. The last location of a file is:
(a) EOF
(b) END
(c) LAST
(d) CLOSE.
Answer: (a) EOF
In simple words: The 'End Of File' (EOF) marker signifies the absolute last location of data within a file.

🎯 Exam Tip: EOF (End Of File) is a standard indicator for reaching the end of a file stream, crucial for loop termination in file reading operations.

Question 2. Which function is used to close a file?
(a) CLOSE
(b) END
(c) EOF
(d) None of these.
Answer: (d) None of these.
In simple words: The correct function to close a file in C is `fclose()`, which is not listed among the options provided.

🎯 Exam Tip: It's important to know the exact function names. The correct function to close a file is `fclose()`. This question tests your specific knowledge of C library functions.

Question 3. Which function is used to read a line from file:
(a) gets ()
(b) fgets ()
(c) readline ()
(d) gets ().
Answer: (b) fgets ()
In simple words: The `fgets()` function is specifically designed to read an entire line of text from a file stream, including the newline character, into a specified buffer.

🎯 Exam Tip: `fgets()` is the safer and preferred function for reading lines from files (or `stdin`) because it allows you to specify the maximum number of characters to read, preventing buffer overflows. `gets()` is generally unsafe.

Question 4. Which function sets the file pointer associated with a stream to a new position:
(a) fseek ()
(b) perror (c) rename (d) rewind.
Answer: (a) fseek ()
In simple words: The `fseek()` function is used to move the file pointer to a specific location within a file, enabling non-sequential (random) access to data.

🎯 Exam Tip: `fseek()` is crucial for random access operations, allowing you to jump to any point in a file. `rewind()` is a specialized form of `fseek()` that resets the pointer to the beginning.