MCQs on Basic Input and Output | Perl

Here are 30 multiple-choice questions (MCQs) based on Chapter 4: Basic Input and Output, covering topics such as reading and writing to files, standard input/output operations, and formatting output with printf and sprintf. These MCQs are designed to test your understanding of file handling and output formatting in Perl.

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Reading and Writing to Files

1. Which of the following file modes opens a file for reading only in Perl?
   • A) ‘w’
   • B) ‘r’
   • C) ‘rw’
   • D) ‘a’
2. What is the correct way to open a file for writing in Perl?
   • A) open($file, ‘r’, ‘file.txt’)
   • B) open($file, ‘w’, ‘file.txt’)
   • C) open($file, ‘a’, ‘file.txt’)
   • D) open($file, ‘rw’, ‘file.txt’)
3. Which function is used to read from a file in Perl?
   • A) write()
   • B) read()
   • C) print()
   • D) <$file>
4. Which function is used to close a file after performing operations in Perl?
   • A) close()
   • B) finish()
   • C) end()
   • D) closefile()
5. How can you check for errors while opening a file in Perl?
   • A) By checking the $! variable
   • B) By using the check() function
   • C) By testing the file descriptor
   • D) By using opencheck()
6. What does the ‘a’ mode in the open() function do in Perl?
   • A) Opens a file for reading
   • B) Opens a file for writing and appending
   • C) Opens a file for reading and writing
   • D) None of the above
7. Which of the following is the correct way to read an entire file into a string in Perl?
   • A) $data = <FILE>;
   • B) $data = read(FILE);
   • C) $data = print(FILE);
   • D) $data = <$file>;
8. What is the correct syntax to write to a file in Perl?
   • A) print FILE “Hello World\n”;
   • B) write FILE “Hello World\n”;
   • C) print “Hello World\n” to FILE;
   • D) write “Hello World\n” to FILE;
9. How can you open a file for both reading and writing in Perl?
   • A) open($file, ‘r+’)
   • B) open($file, ‘w+’)
   • C) open($file, ‘rw’)
   • D) open($file, ‘a+’)
10. What is the output when trying to open a non-existent file in Perl using the ‘r’ mode?

• A) The program creates the file
• B) The program throws an error
• C) The program prints an error message
• D) The program does nothing

Standard Input and Output Operations

11. Which function in Perl is used to print output to the screen?

• A) print()
• B) output()
• C) display()
• D) write()

12. Which function is used to read input from the user in Perl?

• A) input()
• B) readline()
• C) gets()
• D) <STDIN>

13. Which of the following is the correct syntax to read a line of input from the user in Perl?

• A) $input = <STDIN>;
• B) $input = get(STDIN);
• C) $input = readline(STDIN);
• D) $input = input();

14. How can you print output without adding a new line at the end in Perl?

• A) print “Hello”;
• B) print “Hello”, no_newline;
• C) print “Hello”, “\n”;
• D) print “Hello”, “\0”;

15. What does the chomp() function do in Perl?

• A) Removes leading whitespace from a string
• B) Removes the trailing newline from a string
• C) Adds a newline to the end of a string
• D) Checks if a string has a newline character

16. Which of the following prints the value of a variable \$x in Perl?

• A) print $x;
• B) print $x;
• C) print “$x”;
• D) print “$x”;

17. What does the following Perl statement do?
    print “Enter a value: “;
    A) Prints “Enter a value: ” to the file
    B) Prints “Enter a value: ” to the screen
    C) Reads a value from the user
    D) Saves “Enter a value: ” in a variable

18. How do you print formatted text with a specified width in Perl?

• A) printf(“%10s”, $value);
• B) format(“%10s”, $value);
• C) print(“%10s”, $value);
• D) printf($value, “%10s”);

19. What is the function used to read an entire line of input in Perl?

• A) <STDIN>;
• B) readline();
• C) gets();
• D) input();

20. Which of the following is the correct syntax to print a string with variables in Perl?

• A) print(“Hello $name”);
• B) print(‘Hello $name’);
• C) print(Hello $name);
• D) print(Hello + $name);

Formatting Output with printf and sprintf

21. What is the purpose of the printf function in Perl?

• A) It is used to print output with special formatting
• B) It prints raw strings
• C) It reads formatted input
• D) It prints to a file

22. Which of the following correctly formats a number to display two decimal places using printf?

• A) printf(“%.2f”, $number);
• B) printf(“%.2d”, $number);
• C) printf(“%2f”, $number);
• D) printf(“%2.2f”, $number);

23. How can you assign a formatted string to a variable using sprintf in Perl?

• A) $formatted = sprintf(“Hello %s”, $name);
• B) $formatted = sprintf(Hello %s, $name);
• C) $formatted = “sprintf(Hello %s, $name)”;
• D) $formatted = “Hello %s”, $name;

24. Which of the following Perl functions can be used to print output with specific widths for numbers?

• A) printf()
• B) sprintf()
• C) both A and B
• D) print()

25. How would you format an integer with a width of 6 using printf?

• A) printf(“%6d”, $num);
• B) printf(“%d6”, $num);
• C) printf(“6%d”, $num);
• D) printf(“%d”, $num);

26. What is the default separator used by print() for output in Perl?

• A) Space
• B) Comma
• C) Newline
• D) Tab

27. How do you round a floating-point number to 2 decimal places using sprintf in Perl?

• A) $result = sprintf(“%.2f”, $num);
• B) $result = sprintf(“%2f”, $num);
• C) $result = sprintf(“%.2d”, $num);
• D) $result = sprintf(“%2.2f”, $num);

28. Which of the following statements is true about the printf function?

• A) It outputs formatted text to the screen
• B) It reads input from the user
• C) It formats text and writes it to a file
• D) It reads formatted input

29. How can you align text to the right in printf in Perl?

• A) printf(“%-10s”, $text);
• B) printf(“%10s”, $text);
• C) printf(“%s”, $text);
• D) printf(“%-s”, $text);

30. Which function in Perl allows you to format strings without printing them directly?

• A) sprintf()
• B) printf()
• C) print()
• D) format()

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Answer Key

Qno	Answer
1	B) ‘r’
2	B) open($file, ‘w’, ‘file.txt’)
3	D) <$file>
4	A) close()
5	A) By checking the $! variable
6	B) Opens a file for writing and appending
7	A) $data = <FILE>;
8	A) print FILE “Hello World\n”;
9	A) open($file, ‘r+’)
10	B) The program throws an error
11	A) print()
12	D) <STDIN>
13	A) $input = <STDIN>;
14	A) print “Hello”;
15	B) Removes the trailing newline from a string
16	C) print “$x”;
17	B) Prints “Enter a value: ” to the screen
18	A) printf(“%10s”, $value);
19	A) <STDIN>;
20	A) print(“Hello $name”);
21	A) It is used to print output with special formatting
22	A) printf(“%.2f”, $number);
23	A) $formatted = sprintf(“Hello %s”, $name);
24	C) both A and B
25	A) printf(“%6d”, $num);
26	C) Newline
27	A) $result = sprintf(“%.2f”, $num);
28	A) It outputs formatted text to the screen
29	B) printf(“%10s”, $text);
30	A) sprintf()