Write a Python program that takes a user's input as a string.

Display a menu with the following options:

a$.$ Display the length of the input string.

b$.$ Count and display the number of vowels in the input string.

c$.$ Convert the input string to lowercase and display the result.

d$.$ Check if the input string is a palindrome and print the result.

e$.$ Replace a specified character in the input string with another character and display the modified string.

f$.$ Quit the program.

Implement each function corresponding to the menu options $($a to e$)$ as separate functions.

Ensure that the program loops until the user chooses to quit.

Handle invalid menu choices gracefully by displaying an appropriate message.Write a Python program that takes a user's input as a string.

Display a menu with the following options:

a$.$ Display the length of the input string.

b$.$ Count and display the number of vowels in the input string.

c$.$ Convert the input string to lowercase and display the result.

d$.$ Check if the input string is a palindrome and print the result.

e$.$ Replace a specified character in the input string with another character and display the modified string.

f$.$ Quit the program.

Implement each function corresponding to the menu options $($a to e$)$ as separate functions.

Ensure that the program loops until the user chooses to quit.

Handle invalid menu choices gracefully by displaying an appropriate message.