1. CS 116 Tutorial 5 Introduction to Python

2. Review Basic Python Python is a series of statements def f(p1, p2,…pn): x = 5 if x > p1: x = p1 + p2 return x else: return p3 Indentation is extremely important! Using return causes the function produce something All code written after the return on the same indentation line will not be executed. Using return causes the function produce something All code written after the return on the same indentation line will not be executed. Statement1 Statement2 Statement3 … Statementn To make constants: name = value

3. Review Basic Python Useful functions: ◦ +, -, *, /, //, %, ** ◦ and, or, not,, =, ==, != ◦ Math module; use dir(math) to see list Conditions: ◦ if : to start a condition ◦ elif : to continue a condition ◦ else : to execute something if all other conditions are not true (not necessary)

4. Review Python Design Recipe No type Char or Sym New type: Float Examples are comments in the form: # fn_name(p1, p2, … pn) => result Tests: ◦ Make sure to download check.py and put the file in the same folder as your assignment questions check.expect(“name”, fn_name(p1,…pn), result)

5. 1.Write a Python function create_acct_num that consumes a 3-digit number and produces the corresponding 4-digit number, in which the new last digit is remainder when the sum of the digits of the original number is divided by 7. For example, create_account_number(778) => 7781 because 7 + 7 + 8 = 22 and 22/7 has remainder 1

6. 2. Write a Python function shipping_charges that calculates cost of shipping boxes. The function consumes: - a handling charge, - the cost per kg for shipping, - the weight per box (assumed the same for all boxes), and - the number of boxes to ship. The function adds in 13% tax, and returns the total cost. shipping_charges(handling, charge_per_kg, weight_per_box, num_boxes) For example, Shipping_charges(10, 0.25, 10, 5) => 25.425 Note that the value produced may not stored exactly. So, your test should not check for an exact value, but rather should check that your answer is very close to the expected value.

7. 3. Write the accumulatively recursive version of factorial, paying close attention to when you need to use return.

8. 4. If you are given three sticks, you may or may not be able to arrange them in a triangle. If any of the three lengths is greater than the sum of the other two, then you cannot form a triangle. Otherwise, you can. If the sum of two lengths equals the third, they form what is called a "degenerate triangle.” Write a function is_triangl e that consumes three positive integers ( s1, s2, and s3 ) representing the lengths of three sticks and produces one of the following: "No triangle exists" if no triangle can be built with the three sticks "Degenerate triangle exists" if only a degenerate triangle exists for sticks of these lengths "Triangle exists" if a triangle can be made from the sticks