Spring CS Homework 6 p. 1. CS Homework 6

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1 Spring CS Homework 6 p. 1 Deadline 11:59 pm on Friday, March 9, 2018 Purpose CS Homework 6 To practice with some C++ basics, including following design recipe steps for designing and writing simple C++ functions (to be tested and run within the NetBeans IDE as part of the next homework, Homework 7). How to submit Submit your 111hw6.txt file for Homework 6 on the course Canvas site. (Remember, it is good to submit early and often!) Important notes You are still expected to follow the Design Recipe for all functions that you design/define. Remember, you will receive significant credit for the signature, purpose, header, and examples/tests portions of your functions. Typically you'll get at least half-credit for a correct signature, purpose, header, and examples/tests, even if your function body is not correct. (and, you'll lose at least half-credit if you omit these or do them poorly, even if your function body is correct). That said -- remember that, in C++: use C++ type names in the signatures of C++ functions write examples/tests as bool expressions, typically using == or <. For example, my_funct(3) == 27 abs(my_dbl(4.7) ) < and note that these example tests are EXPRESSIONS rather than C++ statements -- do NOT end them with a semicolon! Be especially careful to include at least two examples/tests for every function, including at least one specific example/test for each "kind"/category of data, and (when there are boundaries) for boundaries between data. You can lose credit for not doing so. Be sure to indent your return statement by at least 3 spaces inside your function body! And curly braces go on their own line, lined up as shown in the posted class examples! Homework File Setup Use a program such as (Windows) Notepad or Notepad++ or (Mac OS X) TextWrangler to create a plain text file named 111hw6.txt In one or more C++ comments (single-line or multi-line, your choice!), type: your name, a comment-line containing CS HW 6,

2 Spring CS Homework 6 p. 2 followed by a comment-line giving the date you last modified this homework -- for example: type in YOUR name CS HW 6 last modified: Problem 1 Problem 1 Recall the function from Homework 2, Problem 2 that returns the perimeter of a rectangle. Use the design recipe to design a C++ version of this function named rect_perim. (rect_perim expects the length and width of a rectangle, and returns the perimeter of that rectangle.) On the Week 7 Lab Exercise, you were asked to type an example compound expression calling your functions, then an expression giving the expected value for that call, and then a bool expression that should be true if your example call returns the expected value. This final bool expression is one of the ways we will be writing tests of our functions in C++. So, for circ_area, one of its tests could be written as: circ_area(10) == (PI * 10 * 10) We'll be discussing soon how we will run these tests in C++; in the meantime, for Homework 6, as we did on the Week 7 Lab Exercise, we'll write these tests inside C++ comments, AFTER the purpose statement comment and BEFORE the function header. So, AFTER rect_perim's purpose statement comment and BEFORE its header, write at least TWO such tests for rect_perim, bool expressions that will be true if an expression calling rect_perim with appropriate arguments of your choice is equal to an expression giving the expected value for that example call. Then, complete the function body for rect_perim, placed right after its function header. Problem 2

3 Spring CS Homework 6 p. 3 Problem 2 Recall the fun C++ fact also noted in the Week 7 Lab Exercise: One of the benefits of the C++ string type is that you can use + to append two string instances together -- or even a string and a char*! (At least ONE of the arguments to + has to be a string instance for this to work!) Recall the function from Homework 2, Problem 3 that asks a given person how their day is going. Use the design recipe to design a C++ version of this function named ask_abt_day. (ask_abt_day expects a person's name, and returns a customized question, How's it going,...that person's name...?, asking how their day is going. As in Homework 2, optionally, you may change the exact wording of the question, as long as it includes the person's name and ends with at least one question mark.) AFTER ask_abt_day's purpose statement comment and BEFORE its header, write at least TWO tests for ask_abt_day, bool expressions that will be true if an expression calling ask_abt_day with an appropriate argument of your choice is equal to an expression giving the expected value for that example call. Then, complete the function body for ask_abt_day, placed right after its function header. Problem 3 Problem 3 Recall the function from Homework 2, Problem 5 that computes the total number of feet in a given number of yards and feet. Use the design recipe to design a C++ version of this function named total_feet. (total_feet expects a number of yards and a number of feet, and returns the total number of feet overall in both of these combined.) THIS function does use a named constant! Write a C++ named constant declaration statement creating named constant FEET_PER_YARD, making its value be the number of feet in one yard.

4 Spring CS Homework 6 p. 4 AFTER FEET_PER_YARD's declaration statement and BEFORE total_feet's header, write at least TWO tests for total_feet, bool expressions that will be true if an expression calling total_feet with an appropriate argument of your choice is equal to an expression giving the expected value for that example call. at least ONE of these tests should have 0 as the number of yards argument, at least ONE of these tests should have a number of yards argument greater than 1, (and each of these tests should have a different value for the number of feet argument). Then, complete the function body for total_feet, placed right after its function header. FOR FULL CREDIT, make sure that you USE the named constant FEET_PER_YARD appropriately within total_feet's function body. Problem 4 Problem 4 Recall the function from Homework 2, Problem 6 that computes the total price for an order of Tasty-Waking coffee. Use the design recipe to design a C++ version of this function named order_cost. (order_cost expects the number of pounds of coffee in an order, and returns the total price of that order, including shipping) THIS function also uses named constants -- three of them! Here's how I declared them in the Homework 2 posted example solutions: (define COFFEE-PRICE-PER-LB 6.95) (define SHIP-PRICE-PER-LB 0.75) (define SHIP-COST-FIXED 2.75) Write C++ named constant declarations of these named: COFFEE_PRICE_PER_LB SHIP_PRICE_PER_LB SHIP_COST_FIXED...giving them the correct values. AFTER the named constant declaration statements and BEFORE order_cost's header,

5 Spring CS Homework 6 p. 5 write at least TWO tests for order_cost, bool expressions that will be true if an expression calling order_cost with an appropriate argument of your choice is equal to an expression giving the expected value for that example call. Then, complete the function body for order_cost, placed right after its function header. FOR FULL CREDIT, make sure that you USE the named constants declared above appropriately within order_cost's function body. Problem 5 Problem 5 Recall the function from Homework 3, Problem 2 that computes computes the equivalent Fahrenheit temperature for a given Celsius temperature. Use the design recipe to design a C++ version of this function named cels_to_fahr. (cels_to_fahr expects a temperature given in Celsius, and returns the equivalent Fahrenheit temperature) AFTER cels_to_fahr's purpose statement comment and BEFORE its header, write at least TWO tests for cels_to_fahr, bool expressions that will be true if an expression calling cels_to_fahr with an appropriate argument of your choice is equal to an expression giving the expected value for that example call. Then, complete the function body for cels_to_fahr, placed right after its function header.