FileIO

Question 1

Which is the simpler searching algorithm to implement?

Answer 1

Linear Search

Question 2

Which searching algorithm needs to use a sorted list?

Answer 2

Binary Search

Question 3

What is a text file?

Answer 3

A file consisting of multiple lines of text characters

Question 4

What classes are not standard in Java I/O?

Answer 4

InputFile and OutputFile classes

Question 5

What is the purpose of I/O?

Answer 5

Storing data to ‘nonvolatile‘ devices, e.g. Harddrive

Question 6

What are the two types of streams in Java?

Answer 6

• Text streams * Binary streams

Question 7

What are the two directions of streams in Java?

Answer 7

• Input * Output

Question 8

What are the four base-classes dealing with I/O in Java?

Answer 8

• Reader: text-input * Writer: text-output * InputStream: byte-input * OutputStream: byte-output

Question 9

What character terminates a text file?

Answer 9

The new-line character ‘\n’

Question 10

What is EOF in file processing?

Answer 10

End-of-file character

Question 11

What is the general scheme for reading/writing in Java?

Answer 11

• Open an input/output stream * Read/write next data from/to the stream * Close the stream

Question 12

Which class reads characters from a file?

Answer 12

FileReader Class

Question 13

What does the BufferedReader class do?

Answer 13

Reads a line of text

Question 14

What exception might be thrown during I/O operations?

Answer 14

IOException

Question 15

Try-catch blocks are used for what purpose in I/O?

Answer 15

To handle exceptions

Question 16

What class is used to write characters to a file?

Answer 16

FileWriter class

Question 17

What is the benefit of using BufferedWriter?

Answer 17

Provides efficient writing

Question 18

What should each element in a text file be terminated by?

Answer 18

• Space * Tab * New-line * EOF character

Question 19

What is the difference between binary and text files?

Answer 19

• Binary files are more efficient but not human-readable * Text files are human-readable but less efficient

Question 20

When should you use text files?

Answer 20

For final results if readability is essential

Question 21

What classes simplify file I/O in the uulib package?

Answer 21

• InputFile * OutputFile

Question 22

How do you check for EOF with InputFile?

Answer 22

Using the eof() method

Question 23

What does the readInt() method do in InputFile?

Answer 23

Returns an integer read from the file

Question 24

What is the purpose of close() method in file handling?

Answer 24

To close the file

Question 25

What does BufferedReader.readLine() return if EOF is reached?

Answer 25

null

Question 26

What is a common use case for binary files?

Answer 26

Storing large amounts of data like images or videos

Question 27

What does the PrintWriter class provide?

Answer 27

Print and println methods for writing various types

Question 28

Fill in the blank: The FileOutputStream class is used for _______.

Answer 28

Writing binary files

Question 29

True or False: All files must be closed after operations.

Answer 29

True

Question 30

What is the main drawback of binary files?

Answer 30

Not human-readable

Question 31

What does the InputFile class constructor do?

Answer 31

Opens specified file for input

Question 32

What is the purpose of the FileTotalUnknown class?

Answer 32

To calculate the total of numbers read from a file and print the result.

Question 33

What method is used to read integers from a file in the FileTotalUnknown class?

Answer 33

readInt()

Question 34

What is the output format of the total calculated in the FileTotalUnknown class?

Answer 34

Total is [total]

Question 35

What is the role of the OutputFile class?

Answer 35

To handle output file operations such as creating, closing, and writing data.

Question 36

Which method in OutputFile is used to print a string followed by a new line?

Answer 36

println(String str)

Question 37

How can you write a sequence of integers (1-10) to a file using OutputFile?

Answer 37

By using a loop that calls ofile.println(i) for each integer.

Question 38

What is an example of writing an array of integers to a file?

Answer 38

Using a loop to iterate through the array and calling ofile.println(nums[i]).

Question 39

What is the purpose of creating a reusable method in the FileUtils class?

Answer 39

To write an integer array to a file.

Question 40

What parameters does the writeToFile method in FileUtils take?

Answer 40

int[] nums, String fname

Question 41

In the Bills class, how are total electric and gas bills computed?

Answer 41

By reading from both gas.dat and electric.dat and summing the values.

Question 42

What does the PayRoll class demonstrate?

Answer 42

Reading employee hours and rates from a file and writing their pay to another file.

Question 43

What is the format of each record in the hours.dat file?

Answer 43

Employee number, number of hours worked, and rate per hour.

Question 44

What method is used to check if the end of the file has been reached in the PayRoll class?

Answer 44

eof()

Question 45

In the PayRoll class, how is the pay calculated?

Answer 45

By multiplying hours worked by the rate.

Question 46

What is the output format when writing to pay.dat in the PayRoll class?

Answer 46

Employee number followed by the calculated pay, separated by a tab.

Question 47

What Java I/O classes are used for text input and output stream processing?

Answer 47

FileReader, BufferedReader for input; FileWriter, BufferedWriter, PrintWriter for output.

Question 48

Fill in the blank: The OutputFile class allows you to print a _______ to the file.

Answer 48

[string, integer, float, double]

Question 49

True or False: The FileTotalUnknown class can handle multiple files at once.

Answer 49

False