Due 11:59pm Tuesday, 15 September

Run `update21`, if you haven't already, to create the
`cs21/labs/02`. Then cd into your `cs21/labs/02`
directory and create the python programs for lab 2 in this directory
(handin21 looks for your lab 2 assignments in your cs21/labs/02 directory):

$ update21 $ cd cs21/labs/02 $ pwd /home/your_user_name/cs21/labs/02

Your programs are graded on both correctness and style. Please review
the comments regarding programming style on the main page.

1. Computing volume and surface area of a cone

Write a program, in a file named cone.py, that asks the user to enter the value of the radius and the value of the hight of a cone. Your program will then compute and print out the volume and the surface area of the cone using these formulas:

Here is what two runs of your program might look like:

$ python cone.py This program computes the volume and surface area of a cone given values for the height and radius Enter the radius value: 4 Enter the height of the cone:3 A cone with radius 4 and height 3 has a volume of 50.265 and a surface area of 62.832 $ python cone.py Enter the radius value: 2.3 Enter the height of the cone:0.8 A cone with radius 2.3 and height 0.8 has a volume of 4.432 and a surface area of 17.596Try using string formating to limit the number of places printed beyond the decimal point.

To use math library functions, remember to add this to the **top** of your
program:

from math import *

2. Computing the sum of the first n odd integers

Write a program named oddsum.py, that takes as input a positive integer value n, and then computes the sum of the first n odd integer values. For example, if the user enters 5, your program will compute the sum of 1, 3, 5, 7 and 9.

A couple runs of your program may look like this:

$ python oddsum.py This program computes the sum of the first n odd integers Enter a value for n: 5 the sum of odd integers between 1 and 10 is 25 $ python oddsum.py This program computes the sum of the first n odd integers Enter a value for n: 30 the sum of the odd integers between 1 and 60 is 900It is easy to test your program for correctness because the sum of the first n odd integers is equal to n squared. However, your program should not just compute n squared. Instead, you must use a loop to compute the sum using successive additions.

3. Reverse a phrase

Write a program in a file named reverse.py, that prompts the user to
enter a phrase, and then creates a new string consisting of the
phrase in reverse. The reversed phrase is then printed out.
$ python reverse.py This program produces the reverse of a string entered by the user Enter a phrase: hello there The phrase reversed is ereht olleh $ python reverse.py This program produces the reverse of a string entered by the user Enter a phrase: a man a plan a canal panama The phrase reversed is amanap lanac a nalp a nam a

4. Pattern of stars

Write a program in a file named stars.py, that prompts the user to
enter a value for n, and the prints out n rows of a pattern of
stars that looks like the following examples:
$ python stars.py This program prints out a pattern of stars Enter a value for the size of the pattern: 5 - - - - - * - - - - * * - - - * * * - - * * * * - * * * * * $ python stars.py This program prints out a pattern of stars Enter a value for the size of the pattern: 8 - - - - - - - - * - - - - - - - * * - - - - - - * * * - - - - - * * * * - - - - * * * * * - - - * * * * * * - - * * * * * * * - * * * * * * * *Hint: start by writing a program that prints out these two patterns of stars, then think about how you can use these solutions to lead you to solving the above problem:

```
This program prints out a pattern of stars
Enter a value for the size of the pattern: 5
*
* *
* * *
* * * *
* * * * *
* * * * *
* * * *
* * *
* *
*
```

Extra Challenge

This is not a required part of the lab 2
assignment, but is an extra
challenge that you can try. Only try this after you have completed
all the regular problems in lab 2.
Write a program, morestars.py, that prints out the following patterns of stars given user input values for the size of the patterns:

This program prints out a pyramid of stars Enter a value of for the size of the pyramid: 8 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * This program prints out a diamond of stars Enter a value of for the size of the diamond: 5 * * * * * * * * * * * * * * * * * * * * * * * * *

Submit

Once you are satisfied with your programs, hand them in by typing