STL & Generic Programming

Listing 3: Sample word-count application of std::map

#include<map>
#include<string>
#include<iostream>

std::map<std::string, int> mapWordCount;

// GetNextWord() is a function that reads the next
// word from the text into its argument and returns
// true while there is more to come.
//
std::string strCurrentWord;
while(GetNextWord(strCurrentWord))
{
    // The following line increments the value for the
    // key strWord in the map, creating an entry with
    // value 1 if this is the first occurrence of the word.
    //
   ++(mapWordCount.insert
         (std::make_pair(strCurrentWord, 0)).first->second);
}

// The following loop prints a list of all words and the number 
// of times each of them occurs:
//
std::map<std::string, int>::const_iterator itCurrent = 
    mapWordCount.begin();
std::map<std::string, int>::const_iterator itEnd = 
    mapWordCount.end();
for(;itCurrent!=itEnd; ++itCurrent)
{
   std::cout << itCurrent->first << " "
             << itCurrent->second << "\n";
}
— End of Listing —