Word Frequencies

16.2 Word Frequencies: Design a method to find the frequency of occurrences of any given word in a book. What if we were running this algorithm multiple times?
  • Notes:
    • My approach was to scan through the book, and store the words as keys into a hash table. The word itself will hash to the words frequency. Naturally, this is the best approach with multiple queries as a preprocessing step in every subsequent operation would occur in O(1) time.
#include <sstream>
#include <fstream>
#include <algorithm>
using namespace std;
// command line: process each arguement in the arguement_vector[0 - > arguement count]
int main(int arguement_count, char **arguement_vector)
unordered_map<string, int> myMap;
ifstream file(arguement_vector[1]);
string word;
while (file >> word) {
// if I want lower case words: <algorithm>
transform(word.begin(), word.end(), word.begin(), ::tolower);
auto find = myMap.find(word);
// not found
if (find == myMap.end()) {
myMap.insert({ { word }, { 1 } });
// found
else {