C Programming File I/O Quiz

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Questions and Answers

What should happen when EOF is encountered during file reading?

Reading should terminate. (correct)

An error message should be displayed.

Reading should pause momentarily.

Reading should continue indefinitely.

Which function is used to write a character to a file?

getchar

fclose

putw

putc (correct)

What do the functions fprintf and fscanf handle?

Binary file operations

Mixed data types (correct)

Only string data

Only integer data

Which statement about the getw and putw functions is correct?

They are used for reading and writing integers only. Signup and view all the answers

What will happen if fclose is not called after file operations?

Data may be lost because it won't be written to the disk. Signup and view all the answers

In the fprintf function, what does the control string represent?

The output format for the data being written Signup and view all the answers

How does one read a single integer value from a file?

By using the getw function Signup and view all the answers

What is the primary purpose of the putc function?

To write a character to a file Signup and view all the answers

What major issue arises when handling large volumes of data using console-oriented I/O functions?

Data handling is time consuming and cumbersome. Signup and view all the answers

Which function is used to close an opened file in C?

fclose() Signup and view all the answers

What does the `fopen()` function do?

Creates a new file for use. Signup and view all the answers

What must be specified to the operating system when defining and opening a file?

File name, data structure, and purpose. Signup and view all the answers

Which statement correctly declares a pointer to a FILE type in C?

FILE *fp; Signup and view all the answers

Which function is used to read a character from a file?

getc() Signup and view all the answers

What operation does the `fprintf()` function perform?

Writes a set of data values to a file. Signup and view all the answers

When using `fopen()`, what does the 'mode' parameter indicate?

The purpose of opening the file. Signup and view all the answers

What does the mode 'r' specify when opening a file?

Open the file for reading only. Signup and view all the answers

What is the consequence of not closing an opened file?

Outstanding data may not be flushed from buffers. Signup and view all the answers

What does the function putc(c, fp1) do?

Writes a character to a file pointed by fp1. Signup and view all the answers

In which scenario will fopen() return NULL when using 'w' mode?

The file exists but cannot be overwritten. Signup and view all the answers

What type of variable is 'name' in the example 'fprintf(f1, "%s%d%f", name, age, 7.5);'?

char array Signup and view all the answers

Which error condition can occur when performing I/O operations on a file?

Opening a file as read-only and writing to it Signup and view all the answers

What does the getc function return when the end of a file is reached?

An end-of-file marker (EOF). Signup and view all the answers

Which of the following statements correctly closes a file pointer?

fclose(file_pointer); Signup and view all the answers

Which function is used to check for an end-of-file condition?

feof Signup and view all the answers

When opening a file in 'a' mode and the file does not exist, what happens?

The file is created. Signup and view all the answers

What does the function ferror return when an error has occurred during file processing?

Nonzero integer Signup and view all the answers

Why must a file be closed after operations are completed?

To prevent accidental misuse of the file. Signup and view all the answers

What should be done to handle a situation where fopen returns a NULL pointer?

Check for reasons why the file could not be opened. Signup and view all the answers

Which function can be used to check if an error has occurred up to a certain point during file processing?

ferror Signup and view all the answers

Which option correctly describes the output of the following code: 'if (feof(fp)) printf("End of data.");'?

It prints 'End of data.' if all data has been read from the file. Signup and view all the answers

What may happen if I/O errors are not checked in a program?

The program may terminate prematurely. Signup and view all the answers

What is the purpose of the ftell function?

To save the current position of the file. Signup and view all the answers

What does the rewind function do?

It helps to read the file more than once. Signup and view all the answers

What is the correct syntax for using the fseek function?

fseek(fp, offset, position); Signup and view all the answers

What value does the position parameter of fseek represent when set to 0?

The beginning of the file. Signup and view all the answers

Which statement correctly describes the usage of the fseek function with a negative offset?

It moves the pointer backwards in the file. Signup and view all the answers

What will be the value of n after calling rewind(fp) and then ftell(fp)?

Zero. Signup and view all the answers

Which of the following correctly describes the role of the fseek function?

It can move the file pointer to any location based on specified criteria. Signup and view all the answers

What does the command fseek(fp, 0L, 1) do?

Keeps the pointer at its current position. Signup and view all the answers

Study Notes

File Management in C

File management in C allows handling large data volumes efficiently.
Console-oriented I/O functions have limitations: data loss upon program termination or computer shut-down; cumbersome handling of large data volumes.
Files are locations on disk for storing related data. This overcomes the limitations of traditional input/output methods.
C supports file operations through built-in functions.

File Operations

Naming a file
Opening a file:
- Creating a new file (e.g., fopen("newfile.txt", "w"))
- Opening an existing file (e.g., fopen("existingfile.txt", "r"))
Reading data from a file
Writing data to a file
Closing a file: closes the file, releasing resources.

Standard I/O File Handling Library Functions

fopen(): Creates a new or opens an existing file.
fclose(): Closes an open file.
getc(): Reads a character from a file.
putc(): Writes a character to a file.
fprintf(): Writes formatted data to a file.
fscanf(): Reads formatted data from a file.
getw(): Reads an integer from a file.
putw(): Writes an integer to a file.
ftell(): Returns the current position in a file.
rewind(): Resets the file pointer to the beginning of the file.

Defining and Opening a File

To define and open a file, specify the file name, data structure, and purpose to the operating system.
Declare a FILE pointer variable (e.g., FILE *fp;).
Use fopen() to open the file (e.g., fp = fopen("filename.txt", "mode");).
filename.txt: The name of the file.
mode: Specifies how the file will be used.

Modes for Opening a file (Examples)

r: Opens an existing file for reading only. Will return NULL if the file does not exist.
w: Opens an existing file for writing. If the file exists, it will overwrite its contents; if it does not exist, it will create a new one.
a: Opens an existing or new file for appending (adding) data. If the file exists, it will append the data; if it does not exist, it will create a new one.

Closing a File

Closing a file is essential to ensure all outstanding information is flushed from buffers and to prevent accidental misuse, especially when opening other files or reopening the same in a different mode.
Use fclose(file_pointer) to close the file.

Input/Output Operations on Files

Functions like getc and putc handle basic character-level input/output with files.
getc(file_pointer) reads a character from the file.
putc(character, file_pointer) writes a character to the file.
EOF (end-of-file) is a special value returned by getc when the end of the file is reached, terminating the reading process.

Error Handling During I/O Operations

Errors can occur during file operations in C (e.g., reading beyond end-of-file or device overflow).
feof() checks for the end-of-file condition.
ferror() checks for I/O errors.

Report Unopening a File

If file opening fails, fopen returns a NULL pointer. This can be checked to alert users to potential issues. e.g. if (fp == NULL) {printf("File could not be opened.\n");}

Random Access to Files (Important)

ftell(): Retrieves the current position within a file as a byte offset.
rewind(): Moves the file pointer to the beginning of a file.
fseek(): Moves the file pointer to a specific byte position within a file (taking care to pass valid arguments).
- The first byte of a file is the 0th byte, followed by the 1st, 2nd... (etc).
- fseek uses values for offset and position to help perform random access. offset should be of type long. position should be an integer.

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Description

This quiz covers essential functions and concepts related to file input and output in C programming. Test your knowledge on file handling functions like fopen, fclose, fprintf, and their respective operations. Prepare to understand error handling and data management when working with files in C.