Vector, String and Iterator
Youll 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, youll print the list twice, once using the index operator and then using an iterator to traverse the list. When youre 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
program
read
really see sort test this this to words
Ive 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 dont need to change whats 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 wont 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, dont use the simplified for loop syntax, for ( type var : some_container ). I want you to try using iterators directly.
When youre done, submit a copy of your completed sortWords.cpp file using the exercise_25 assignment on Moodle.
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