What is the output of the following code? int a = 5; int *p = &a; int **q = &p; printf("%d", **q);

The correct answer is A: 5. q is a pointer to pointer p. **q dereferences both pointers, giving the value of a, which is 5.

What is the key difference between a structure and a union in C?

The correct answer is B: Structure allocates memory equal to sum of all members, union allocates memory equal to the largest member. In structures, memory is allocated for each member independently. In unions, all members share the same memory location, so total memory allocated equals the size of the largest member.

Which of the following is TRUE about inline functions in C99 standard?

The correct answer is B: They are hints to the compiler to expand function code inline. The 'inline' keyword is a hint to the compiler to replace function calls with the function body, reducing overhead but increasing code size.

Which scenario demonstrates a dangling pointer?

The correct answer is B: Pointer freed but still used afterward. Dangling pointer occurs when memory is freed but pointer still references that location. This causes undefined behavior.

Which of the following correctly initializes a 2D array of integers?

The correct answer is A: int arr[3][3] = {1,2,3,4,5,6,7,8,9};. Option A is valid - 2D arrays can be initialized with all elements in a single brace. Options B and C are invalid as at least one dimension must be specified.

Home

Home › Subjects › C Programming › File Handling

C Programming
File Handling

C language from basics to advanced placement prep

27 Q 10 Topics Take Mock Test

Difficulty: All Easy Medium Hard 1–10 of 27

Topics in C Programming

All Basics & Syntax 86 Data Types & Variables 97 Control Flow 100 Functions 99 Arrays & Strings 100 Pointers 99 Structures & Unions 100 File Handling 100 Dynamic Memory 98 Preprocessor 99

Q.1 Easy File Handling

In a file processing application, what is the primary difference between 'wb' and 'w' file modes?

A 'wb' opens in binary mode while 'w' opens in text mode

B 'w' is faster than 'wb'

C 'wb' allows reading while 'w' does not

D There is no difference in modern C compilers

Correct Answer: A. 'wb' opens in binary mode while 'w' opens in text mode

EXPLANATION

'w' opens file in text mode (converts line endings), while 'wb' opens in binary mode (no conversion). This matters when handling platform-specific line endings (\r\n vs \n).

Test

Q.2 Easy File Handling

Which function is used to check if the end-of-file (EOF) has been reached in C file handling?

A feof(fp)

B eof(fp)

C iseof(fp)

D checkeof(fp)

Correct Answer: A. feof(fp)

EXPLANATION

feof() is the standard C library function that returns non-zero if EOF has been reached on the given file stream. Other options are not valid C functions.

Test

Q.3 Easy File Handling

Which mode opens file in text format with write permission only?

A wb

B w

C wt

D wa

Correct Answer: B. w

EXPLANATION

'w' mode opens file in text format for writing. 'wb' is binary write. 'wt' is explicitly text write but 'w' is default text mode.

Test

Q.4 Easy File Handling

Which function returns the current position of file pointer?

A fgetpos()

B ftell()

C fseek()

D rewind()

Correct Answer: B. ftell()

EXPLANATION

ftell() returns the current file position as a long integer. fgetpos() stores position in a fpos_t structure. rewind() resets to beginning.

Test

Q.5 Easy File Handling

What does fseek(fp, 0, SEEK_END) accomplish?

A Moves pointer to beginning of file

B Moves pointer to end of file

C Moves pointer to current position

D Closes the file pointer

Correct Answer: B. Moves pointer to end of file

EXPLANATION

SEEK_END moves the file pointer to the end of file. SEEK_SET goes to beginning, SEEK_CUR to current position.

Test

Q.6 Easy File Handling

Which file opening mode allows both reading and writing without truncating existing content?

A r+

B w+

C a+

D x+

Correct Answer: A. r+

EXPLANATION

Mode 'r+' opens file for reading and writing without truncating. 'w+' truncates the file, 'a+' appends, and 'x+' is for exclusive creation.

Test

Q.7 Easy File Handling

In C file handling, what does rewind(fp) do?

A Moves the file pointer to the beginning of the file

B Closes and reopens the file

C Moves the file pointer to the end of the file

D Flushes the file buffer

Correct Answer: A. Moves the file pointer to the beginning of the file

EXPLANATION

rewind(fp) repositions the file pointer to the start of the file. It's equivalent to fseek(fp, 0, SEEK_SET).

Test

Q.8 Easy File Handling

What is the return value of feof(fp) when the end of file is reached?

A Non-zero value (true)

B Zero (false)

C -1

D NULL pointer

Correct Answer: A. Non-zero value (true)

EXPLANATION

feof(fp) returns a non-zero value when EOF (End Of File) is reached, and returns zero when not at EOF.

Test

Q.9 Easy File Handling

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

A fputc()

B fgetc()

C fwrite()

D fprintf()

Correct Answer: A. fputc()

EXPLANATION

fputc() writes a single character to the specified file. fgetc() reads a character, fwrite() writes blocks, and fprintf() writes formatted output.

Test

Q.10 Easy File Handling

What does the 'w+' mode do when opening a file with fopen()?

A Opens file for reading and writing, creates if doesn't exist

B Opens file for writing only, appends data at end

C Opens file for reading only

D Opens file in binary write mode

Correct Answer: A. Opens file for reading and writing, creates if doesn't exist

EXPLANATION

'w+' mode opens a file for both reading and writing. If the file doesn't exist, it creates a new one. If it exists, it truncates the file to zero length.

Test

1 2 3

All Subjects & Topics

Govt. Exams

Entrance Exams

Teacher Exams

Subjects

Quick Links

C Programming File Handling

C Programming
File Handling