Spring CS Homework 12 p. 1. CS Homework 12

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1 Spring CS Homework 12 p. 1 Deadline 11:59 pm on Friday, May 4, 2018 Purpose CS Homework 12 To practice with sentinel- and question-controlled loops, file input and file output, and writing functions with a return type of void (that do not return anything, such as Week 11 Lecture 2's function print_greet). How to submit Submit your main.cpp (or it may be renamed as well, as long as it ends in.cpp) file for this lab on (Remember, it is good to submit early and often!) You will ALSO be submitting several.txt files for this homework, as described in the problems below. (It is not REQUIRED for this homework -- but if you would LIKE to write any of the non-main functions in their own.h and.cpp files, as demonstrated with function cheer during Week 13 Lecture 2, you may! Just be sure to submit all of your lab's.h and.cpp files in that case.) Important notes IF you would like: FEEL FREE to include additional cout's of endl or spacing or headings between testing calls of different problems if you would like to have more-readable program output! 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). Be sure to follow class coding standards! Homework 12 Program Setup Start NetBeans. From the File menu, select New Project.... Select Category of C/C++ and Project of C/C++ Application, and click Next>. Type 111hw12 in the Project Name box, and use Browse... to direct the Project Location folder to your desired location. (REMEMBER: in an HSU lab, this needs to be to the U: drive or to a flash drive.) You can rename the main.cpp file if you would like -- all other options should remain as they are. Then select "Finish". In the left-side window, expand the Source Files section, then double-click on the name of the file containing your main function this should open an editor window with the contents of that file. REPLACE its current contents with the "first main.cpp template" from the CS 111 public course web site, under "References".

2 Spring CS Homework 12 p. 2 (You can REMOVE, or just not paste in, the very first "FIRST VERSION" comment.) Find the comment that has by: and last modified: START that comment with: CS HW 12 Then put your name after by:, and today's date after last modified:. For example: /*--- CS HW 12 by: Your Name last modified: */ On the course Canvas site, on the Homework 12 assignment link, you will find links to some provided header and source code files for some functions you are to use in this homework assignment. ADD them to this project by doing the following: From Canvas, go to the Homework 12 assignment link, click on each of the links for each of these listed files, and DOWNLOAD each into the project folder for your project 111hw12: do_op.h do_op.cpp get_worth.h get_worth.cpp sum_worth.h sum_worth.cpp Now, in NetBeans, in the Project window on the left, for EACH of the following files, right-click on the Header Files folder for project 111hw12, select "Add Existing Item...", highlight THAT file from the 111hw12 folder, and click the "Select" button to add it to the header files for your project: do_op.h get_worth.h sum_worth.h Then, in NetBeans, in the Project window on the left, for EACH of the following files, right-click on the Source Files folder for project 111hw12, select "Add Existing Item...", highlight THAT file from the 111hw12 folder, and click the "Select" button to add it to the source files for your project: do_op.cpp get_worth.cpp sum_worth.cpp Now, open the file containing your main function, and where you see: #include <cstdlib>

3 Spring CS Homework 12 p. 3 #include <iostream> #include <string> #include <cmath> using namespace std; now ADD the following #includes BEFORE the using namespace std; line as shown: #include <cstdlib> #include <iostream> #include <string> #include <cmath> #include "do_op.h" #include "get_worth.h" #include "sum_worth.h" using namespace std; Now you should be able to use any of the functions provided in these files in all of the functions, including the main function, in this file! COME to office hours EARLY in the week if you would like help with the above! Problem 1 Find the comment: /*--- PUT YOUR SIGNATURES, PURPOSES, and FUNCTION DEFINITIONS HERE ---*/ After this comment, type a blank link, and then type the comment: Problem 1 You will practice writing a sentinel-controlled while loop in this problem. Problem 1 IMPORTANT REMINDER!! FIRST: remember that the C++ iostream library includes a function, getline, that lets you read everything the user types -- even blanks! -- up to but not including enter/return: getline(cin, string_to_read_into); (It expects an input stream, for our purposes in this problem cin, and a local string variable, and it has the side-effect of setting that local string variable to what the user types up to but not including enter/return, read in and treated as a string. It behaves a bit oddly when you mix it with cin <<, BUT when used just with other calls to getline it is quite reasonable.) For our purposes here, note that if the user immediately types enter/return, an empty string -- "" -- is read into that local string variable that is its second argument....back to YOUR Problem 1 task: A user might like a version of Homework 11 Problem 3's sum_worth that allows them to enter MORE than one string of coin characters. So......for practice writing a sentinel-controlled-style while loop, write a function sum_worth_ask that expects nothing, returns nothing (so it will have a return type of void), and has the side-effect of serving as a repeated-interactive front-end for the function sum_worth. That is, your function will repeatedly prompt the user to enter a string of coin characters, and then use sum_worth to determine the worth of the coins in the entered string and print to the screen a polite,

4 Spring CS Homework 12 p. 4 readable message telling the user the worth of the coins in the entered coin-characters string, until the user indicates that they would like to stop by entering the special sentinel value. For this function, the user entering an empty coin-string -- just typing enter/return when prompted -- would make for a quite reasonable sentinel value. ALSO keep a running total of the worth of all of the strings entered by the user, and after the user enters the special sentinel value, print a final polite, readable message telling the user the total worth of ALL of the entered coin-character strings they entered during that function run. Make sure that this function uses a properly structured sentinel-controlled while loop (as described in Week 14 - Lecture 1 and in the Week 14 Lab Exercise - Problem 2) in asking the user to enter the next coin-characters string. Be sure to include what the user needs to type in to quit as part of your question to the user! This function is expected to appropriately call sum_worth to determine the worth of each entered coinstring. This function should allow the user to enter an empty coin character string by using the function getline to read in the entered coin-characters string This is tricky to test, because it is all side-effects -- include at least one call to sum_worth_ask in your main function, and test-run it on an appropriate variety of test input until you are convinced it is working properly. (In this case, it is also wise to test it on a case in which the user immediately enters the sentinel value, the first time they are asked. What should happen in that case?) Problem 2 After Problem 1's sum_worth_ask, (before your main function), type a blank link, and then type the comment: Problem 2 You will practice writing a question-controlled while loop in this problem. Consider the do_op function from Homework 8 - Problem 6, that expects an operator expressed as a character and two numbers, and returns the result of performing the operator corresponding to that character to those two numbers. To practice writing a question-controlled while loop, write a function do_op_ask that expects nothing, returns nothing (so it will have a return type of void), and has the side-effect of serving as a repeatedinteractive front-end for the function do_op. That is, your function will repeatedly ask the user if they would like to do another computation, and if they answer yes, it prompts the user to enter a character and two numbers, and then prints to the screen, in an appropriate descriptive message, the value that do_op returns for those arguments. It will keep doing this until the user doesn't answer yes. Make sure that this function uses a properly structured question-controlled while loop (as described in Week 14 - Lecture 1 and in the Week 14 Lab Exercise - Problem 3) You get to decide what will be considered as a "yes" answer Make sure your instructions to the user make it clear what they need to type to continue and to stop. Make sure that this function appropriately calls do_op.

5 Spring CS Homework 12 p. 5 This, also, is tricky to test, because it is all side-effects -- include at least one call to do_op_ask in your main function, and test-run it on an appropriate variety of test input until you are convinced it is working properly. (In this case, it is also wise to test it on a case in which the user immediately answers no, the first time they are asked. What should happen in that case?) Problem 3 After Problem 2's do_op_ask, (before your main function), type a blank link, and then type the comment: Problem 3 You will practice writing to a file in this problem. Problem 3 IMPORTANT REMINDER!! You can use the string method c_str to generate a char* string FROM a string object: your_string_variable_name.c_str()...which turns out to be very useful when a string local variable contains the name of a file to be opened, since, for at least some C++ compilers, the file stream's open method is one of the rare situations where an old-style C-string of type char* is required...!...back to YOUR Problem 3 task: To practice writing to a file, write a function fill_file that expects the name of a file the user wants to create, and it returns nothing (so it will have a return type of void), and has the side-effects of creating a file with the given name (in the current directory/project folder) if it does not already exist, and interactively filling it with desired contents, line by line. It should interactively ask for lines of file content that should be written to a file with the given name. You are expected to use function getline to read in the lines that are to be written to the file. Remember, getline expects the input stream as its first argument -- so, here, reading from the user, that will be cin -- and the string whose value is to be what is typed in as its second argument. For this problem, you get to CHOOSE whether to use: a for-loop (to ask for a set number of lines from the user), a sentinel-controlled while loop, or a question-controlled while loop. Don't forget to close your output file stream when you are done! This, yet again, is tricky to test, but at least it expects a parameter! So, here: include at least TWO calls to fill_file in your main function, using it to create at least TWO files whose names include prob3 in their names, and whose names end in.txt (for example, prob3-1.txt and prob3-2.txt). ALSO submit these resulting at-least-two *prob3*.txt files from running these tests!

6 Spring CS Homework 12 p. 6 Problem 4 After Problem 3's fill_file, (before your main function), type a blank link, and then type the comment: Problem 4 You will practice reading from a file in this problem. Write a function read_quants that expects the name of a file assumed to contain JUST positive integer quantities to read, returns nothing (so it will have a return type of void), and has the side-effect of reading and then DOING something of your choice with each positive integer quantity it reads, and then writing the result to the screen. (for example -- you could do some computation with that positive integer quantity, or repeat some action that positive integer quantity of times, or you could call cheer or starline or starbox with that positive integer quantity, etc.!) Given how fstream file input works, you may just trust that the user provides you with input files containing only integers (and it is their fault and problem if they don't). BUT, OPTIONALLY, you may decide IF you would like to test if they gave you only positive integers in that file, and complain and refuse to do your chosen action on any that are not positive. You can write almost-reasonable tests for read_quants...!: Use NotePad++/TextWrangler or (carefully!) your fill_file program from Problem 3 to create AT LEAST TWO example files for testing read_quants whose names include prob4 in their names, and that end in.txt (for example, prob4-1.txt and prob4-2.txt). ALSO submit these example input files! In your main function, you can test read_quants by calling twice, with these two example files you created, PRECEDING each of these by printing to the screen a description of what SHOULD be the side-effects of that call.