Exercise

What to do?

1. Write a program that takes a user-input string and displays the character at a specified index entered by the user.
2. Create a program that prompts the user to enter a string and converts all uppercase letters to lowercase. Display the modified string.
3. Develop a program that accepts a user-input string and converts all lowercase letters to uppercase. Show the modified string as output.
4. Write a program that concatenates two strings provided by the user and displays the resulting concatenated string.
5. Design a program that asks the user to input a string and extracts a specific portion (slice) based on the user-provided start and end indices. Display the sliced string. Create a program that requests the user's name as input and then displays a greeting message with the name using formatted output.
6. Develop a program that calculates the area of a circle (taking the radius as input) and displays the result formatted to two decimal places.