2.4.1 - Formatted Functions.

1. Which of the following functions is used to display output on the screen in C?

(A) scanf()
(B) gets()
(C) printf()
(D) puts()

Correct Answer: (C) printf().

2. What is the purpose of the scanf() function in C?

(A) To display output on the screen
(B) To perform calculations
(C) To receive input from the user
(D) To write data to a file

Correct Answer: (C) To receive input from the user.

3. What is the correct format specifier to scan an integer using scanf()?

(A) %f
(B) %d
(C) %c
(D) %s

Correct Answer: (B) %d.

4. Which of the following format specifiers is used to scan or print a floating-point number?

(A) %d
(B) %f
(C) %c
(D) %s

Correct Answer: (B) %f.

5. What does the format specifier %c represent in C's scanf() and printf() functions?

(A) Scan or print a string
(B) Scan or print an integer
(C) Scan or print a floating-point number
(D) Scan or print a character

Correct Answer: (D) Scan or print a character.

6. Which of the following format specifiers is used to scan or print a string in C?

(A) %f
(B) %c
(C) %d
(D) %s

Correct Answer: (D) %s.

7. In C, the format specifier %lf is used to scan or print which type of data?

(A) Integer
(B) Character
(C) Double
(D) String

Correct Answer: (C) Double.

8. Which of the following is a formatted input/output function in C?

(A) gets()
(B) puts()
(C) scanf()
(D) fgetc()

Correct Answer: (C) scanf().

9. What header file is required for using scanf() and printf() functions in C?

(A) stdlib.h
(B) stdio.h
(C) math.h
(D) string.h

Correct Answer: (B) stdio.h.

10. What is the correct output for the following C code?

                #include <stdio.h>
                int main() {
                    int num;
                    printf("Enter an integer: ");
                    scanf("%d", &num);
                    printf("The integer is %d", num);
                    return 0;
                }

(A) Enter an integer: (user input)
(B) Enter an integer: (user input) The integer is (user input)
(C) The integer is (user input)
(D) Compilation error

Correct Answer: (B) Enter an integer: (user input) The integer is (user input).

2.4.2 - Unformatted Functions.

11. What does the getchar() function do in C?

(A) Reads a single character from the standard input and returns it as an integer.
(B) Writes a single character to the standard output.
(C) Reads a string from the standard input until a newline is encountered.
(D) Writes a string to the standard output with a trailing newline.

Correct Answer: (A) Reads a single character from the standard input and returns it as an integer.

12. How does the putchar() function work?

(A) It reads a single character from the standard input.
(B) It writes a single character to the standard output.
(C) It reads a string from the standard input until a newline is encountered.
(D) It writes a string to the standard output with a trailing newline.

Correct Answer: (B) It writes a single character to the standard output.

13. What is the purpose of the gets() function?

(A) To read a single character from the standard input.
(B) To write a single character to the standard output.
(C) To read a line of text from the standard input until a newline or end-of-file is encountered.
(D) To write a line of text to the standard output without a trailing newline.

Correct Answer: (C) To read a line of text from the standard input until a newline or end-of-file is encountered.

14. What does the puts() function do?

(A) Reads a line of text from the standard input.
(B) Writes a line of text to the standard output with a trailing newline.
(C) Writes a single character to the standard output.
(D) Reads a single character from the standard input and returns it.

Correct Answer: (B) Writes a line of text to the standard output with a trailing newline.

15. Which function would you use to read multiple characters in a loop?

(A) putchar()
(B) gets()
(C) puts()
(D) getchar()

Correct Answer: (D) getchar().

16. Which function is typically used to display a single character on the screen?

(A) gets()
(B) puts()
(C) getchar()
(D) putchar()

Correct Answer: (D) putchar().

17. What happens if you use gets() without a buffer large enough to hold the input?

(A) The input will be truncated.
(B) The program will crash.
(C) The input will be stored correctly, and the buffer will expand.
(D) The input will be ignored.

Correct Answer: (B) The program will crash.

18. Which function should be used if you want to display a string with a newline at the end?

(A) getchar()
(B) putchar()
(C) gets()
(D) puts()

Correct Answer: (D) puts().

19. How can you read more than one character using getchar()?

(A) Use it in a loop to read characters one by one.
(B) Use it with a buffer to read multiple characters at once.
(C) Use it to read a string directly.
(D) It cannot be used to read more than one character.

Correct Answer: (A) Use it in a loop to read characters one by one.

20. Which of the following is true about gets() and fgets()?

(A) gets() is safer than fgets().
(B) fgets() allows specifying the maximum number of characters to read, whereas gets() does not.
(C) gets() and fgets() are functionally identical.
(D) fgets() does not read input from the standard input.

Correct Answer: (B) fgets() allows specifying the maximum number of characters to read, whereas gets() does not.

2.4.3 - fprintf(), fscanf(),sprintf(), and sscanf().

21. What is the primary purpose of the fprintf() function in C?

(A) To print formatted data to the console.
(B) To read formatted data from a file.
(C) To write formatted data to a file.
(D) To write unformatted data to the console.

Correct Answer: (C) To write formatted data to a file.

22. How does the fscanf() function work in C?

(A) It writes formatted data to a file.
(B) It reads formatted data from a file based on the provided format.
(C) It prints formatted data to the console.
(D) It reads a single character from a file.

Correct Answer: (B) It reads formatted data from a file based on the provided format.

23. Which function is used to read formatted data from a string buffer and store it in variables?

(A) sprintf()
(B) fprintf()
(C) sscanf()
(D) fscanf()

Correct Answer: (C) sscanf().

24. What does the sprintf() function do?

(A) Reads formatted data from a file.
(B) Formats and stores values in a character array.
(C) Prints formatted data to the console.
(D) Reads formatted data from the console.

Correct Answer: (B) Formats and stores values in a character array.

25. What is the key difference between fprintf() and printf()?

(A) fprintf() writes to a file, while printf() writes to the console.
(B) fprintf() reads from a file, while printf() reads from the console.
(C) fprintf() formats data, while printf() does not.
(D) fprintf() and printf() are functionally identical.

Correct Answer: (A) fprintf() writes to a file, while printf() writes to the console.

26. Which function would you use to read formatted data from a string buffer?

(A) fprintf()
(B) fscanf()
(C) sscanf()
(D) sprintf()

Correct Answer: (C) sscanf().

27. When using sprintf(), what should be considered regarding the buffer size?

(A) The buffer size should be exactly the size needed for the output.
(B) The buffer size should be slightly larger than the anticipated output size.
(C) The buffer size is not important as sprintf() dynamically allocates memory.
(D) The buffer size should be the same as the size of the input string.

Correct Answer: (B) The buffer size should be slightly larger than the anticipated output size.

28. What is the role of the format parameter in fscanf() and fprintf() functions?

(A) To specify the output format of the data.
(B) To specify the type of data to read or write.
(C) To indicate the file to be used.
(D) To determine the size of the buffer.

Correct Answer: (B) To specify the type of data to read or write.

29. Which function would you use to print formatted data to the console?

(A) fprintf()
(B) fscanf()
(C) sscanf()
(D) printf()

Correct Answer: (D) printf().

30. If you need to read formatted data from a file using a file pointer, which function would you use?

(A) sprintf()
(B) fprintf()
(C) fscanf()
(D) sscanf()

Correct Answer: (C) fscanf().

31. What is the main purpose of the sscanf() function?

(A) To write formatted data to a file.
(B) To print formatted data to the console.
(C) To read formatted data from a string.
(D) To read formatted data from the console.

Correct Answer: (C) To read formatted data from a string.

32. How do you handle errors when using the fprintf() function?

(A) Check the return value; if it is negative, an error occurred.
(B) Use a specific error handling function for fprintf().
(C) fprintf() does not support error handling.
(D) Errors are automatically handled by the compiler.

Correct Answer: (A) Check the return value; if it is negative, an error occurred.

33. What should be done if fscanf() does not read data as expected?

(A) Verify the format specifier matches the data in the file.
(B) Ensure the file pointer is correctly initialized.
(C) Check the buffer size used in fscanf().
(D) Increase the file permissions for reading.

Correct Answer: (A) Verify the format specifier matches the data in the file.

34. Which function should you use if you need to format values into a character array without printing them?

(A) fscanf()
(B) sprintf()
(C) sscanf()
(D) fprintf()

Correct Answer: (B) sprintf().

35. How do sprintf() and sscanf() differ from printf() and scanf()?

(A) sprintf() and sscanf() handle strings, while printf() and scanf() handle console I/O.
(B) sprintf() and sscanf() are used for file I/O, while printf() and scanf() are used for string manipulation.
(C) sprintf() and sscanf() handle console I/O, while printf() and scanf() handle file I/O.
(D) sprintf() and sscanf() are used for reading and writing directly to/from files.

Correct Answer: (A) sprintf() and sscanf() handle strings, while printf() and scanf() handle console I/O.

36. In which scenario would you use sprintf() over printf()?

(A) When you need to store formatted data in a string rather than printing it.
(B) When you need to print formatted data to the console.
(C) When you need to read formatted data from a file.
(D) When you need to write formatted data to a file.

Correct Answer: (A) When you need to store formatted data in a string rather than printing it.