Python 100 Questions, 100 Python Problems with Solutions for Beginners | Most Common Python Programs for Practice !! BY Rakesh !!

11. Write a function to calculate the square of a number without using the ** operator.

12. Write a function to convert Celsius to Fahrenheit.

13. Write a function to convert Fahrenheit to Celsius.

14. Write a function to reverse a string.

15. Write a function that counts the number of vowels in a given string.

16. Write a function that counts the number of words in a sentence.

17. Write a function that takes a list of strings and returns the list sorted in alphabetical order.

18. Write a function that checks if a string is a valid email address.

19. Write a function that takes a list of numbers and returns the median.

20. Write a function that checks if a string is a valid palindrome considering only alphanumeric characters and ignoring cases.