C++ Primer, Fifth Edition

Using a set

A logical extension to our program is to ignore common words like “the,” “and,” “or,” and so on. We’ll use a set to hold the words we want to ignore and count only those words that are not in this set:

// count the number of times each word occurs in the inputmap<string, size_t> word_count; // empty map from string to size_tset<string> exclude = {"The", "But", "And", "Or", "An", "A",                       "the", "but", "and", "or", "an", "a"};string word;while (cin >> word)    // count only words that are not in exclude    if (exclude.find(word) == exclude.end())        ++word_count[word];   // fetch and increment the counter for word

Like the other containers, set is a template. To define a set, we specify the type of its elements, ...