Computer Science

Faculty of Engineering, LTH

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Exercise 6

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Template functions, containers, algorithms.   exercise6.tar.gz  sol-exercise6.tar.gz 
  1. "Counting sort" is an efficient sorting method if the elements that are to be sorted are integral values in a limited range. You count the number of occurrences of each value and then output each value the correct number of times.  

    Example: sort {6, 3, 6, 2, –1, 3}. The number of occurrences becomes {1, 0, 0, 1, 2, 0, 0, 2} (one –1, no 0, no 1, one 2, two 3, no 4, no 5, two 6).  

    Implement the function csort in Sort some million values in the range [1, 1000] and compare the execution time for csort with that of std::sort. csort should be better. Sort some thousand values in the range [–10 000 000, +10 000 000] and compare again.  

  2. Write a class SequenceGenerator to be used in Deduce from the program text what the class should look like.  

  3. Write a program that reads a number of text files, whose names are given on the command line, and prints the 20 most common words in the files along with the total number of occurrences in all files. You may assume that there are only letters and whitespace in the files. Give an error message if a file cannot be opened.