STL & Generic Programming: STL Container Iterators
By Thomas Becker, April 01, 2001
We've all heard we can use iterators "just like pointers, but that isn't the whole story. Some iterators are important for what they won't let you do - especially when protecting the integrity of a container
April 2001/STL & Generic Programming/Listing 1
#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(strWord, 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 —
