# Exercise 6-0

Compile, execute, and test the programs in this chapter.

# Solution

In Chapter 6 of the textbook there are 7 core concepts / programs introduced. For ease of documentation I shall dice this up into 7 parts as followings – simply click the hyperlink to drill down to see the post corresponding to the particular part.

Exercise 6-0 (Part 1 / 7): Relating to section 6.1 of the textbook (page 101-103). There are many ways to append elements from container B to container A (the base). In this post I shall implement and test out 3 known ways to do this: (1) pusb_back method, (2) insert method, and (3) copy method. The test confirms that all 3 methods produce the same results.

Exercise 6-0 (Part 2 / 7): Relating to section 6.1.1 of the textbook (page 103-105). Implement and test out an alternative way to split a line into words using the find_if utility from the <algorithm> directive. The original split function method was first introduced in S5.6/88 of the book.

Exercise 6-0 (Part 3 / 7): Relating to section 6.1.2 of the textbook (page 105). Implement and test out the home-made isPalindrome function (created using the equal utility). Note that this is a more neat / compact version to the created in my previous Solution to Exercise 5-10.

Exercise 6-0 (Part 4 / 7): Relating to section 6.1.3 of the textbook (page 105-109). Implement and test out the “Finding URLs” program. The program scans a line of input text, and automatically detect and display all the URL addresses within that line of text.

Exercise 6-0 (Part 5 / 7): Relating to section 6.2 of the textbook (page 110-116). Implement and test out the “Comparing Grading Schemes” program. This program reads in a set of student’s grades (from mid-term exam, final exam, and individual homework grades), compute the student’s final grades using the 3 grading schemes (median homework, average homework, and optimistic-median homework), split the students into two groups (did and didn’t do all homework), and for each group compute the group medians associating with the grading schemes. i.e. the end result consists of 6 total grades: medians computed using the 3 schemes for group A (students who did all homework), and medians computed using the 3 schemes for group B (students who didn’t do all homework). The exercise introduces one key idea: parsing a function as an argument to another function. From Chapter 10 we shall see this is actually facilitated by the “hidden” pointer and array mechanism.

Exercise 6-0 (Part 6 / 7): Relating to section 6.3.1 of the textbook (page 117-118). Implement and test out the “two-pass extract_fails” program. This program essentially split the students into two groups – failed and passed students. This version of extract_fails function uses remove_copy_if and erase from the <algorithm> directive. (Note that the original version of extract_fails function was first introduced in Chapter 5 / my Solution to Exercise 5-0.

Exercise 6-0 (Part 7 / 7): Relating to section 6.3.2 of the textbook (page 119-120). Building on the previous exercise the author introduces an even better “one-pass extract_fails” program which takes half the time to run in comparison to the “two-pass” version. This version of extract_fails function uses the stable_partition and erase from the <algorithm> directive.