CSC230-Exercise 25 Vector, String and Iterator Solved

You'll find a source file, sortWords.cpp and an input file, input.txt on the course homepage.  You can also download the exercise files with the following curl commands:

curl -O https://www.csc2.ncsu.edu/courses/csc230/exercise/exercise25/sortWords.cpp curl -O https://www.csc2.ncsu.edu/courses/csc230/exercise/exercise25/input.txt curl -O https://www.csc2.ncsu.edu/courses/csc230/exercise/exercise25/expected.txt

The job of this program is to read a list of words from standard input, sort them using the sort() template algorithm.  Then, you'll print the list twice, once using the index operator and then using an iterator to traverse the list.  When you're done, you should be able to run the program like this:

$ ./sortWords < input.txt

-- Backward -words to this this test sort

see

really read program

print of of

list

it

is

if

can and and a a

-- Forward -a a and and can if

is it

list of of

print

program

read

really see sort test this this to words

I've left several places for you to add code:

•   First, fill in the function parameter for readWords() to pass in the word list by reference.  The printBackward() and printForward() functions don't need to change what's on the word list, so you can pass it by const reference for them.

•   Fill in the body of readWords() to read a list of words from standard input and store them in the vector of words.  Remember, you can use the operator to read into strings from standard input.  It will read space-delimited tokens (i.e., words).

•   In main, add code to call the sort() template algorithm to sort the word list in lexicographic order.  Remember, by default sort() will compare elements using their less-than operator, and less than on strings compares them in lexicographic order, so ...

•   Fill in the body of printBackword() to use the index operator (e.g., words[ i ]) to print the word list in reverse sorted order, one word per output line (starting with the last word on the list and ending with the first word).

•   Fill in the body of printForward() to use iterators to print the word list in sorted order, one word per output line. Use the auto keyword when you declare the iterator variable.  Iterators for traversing a const container have a slightly different type, const_iterator rather than iterator.  With auto, you won't have to worry about this. The compiler will figure out the type the iterator needs to have based on the type of the value you initialize it with.

For this part, don’t use the simplified for loop syntax, for ( type var : some_container ).  I want you to try using iterators directly.