C++ examples for STL:map
Find an element for its key in a map
#include <iostream> #include <string> #include <map> using namespace std; void show(const char *msg, map<string, int> mp); int main() {// w w w . j a va 2 s . c om // Declare an empty map that holds key/value pairs // in which the key is a string and the value is an int. map<string, int> m; // Insert characters into m. An iterator to the inserted // object is returned. m.insert(pair<string, int>("Alpha", 100)); m.insert(pair<string, int>("Gamma", 300)); m.insert(pair<string, int>("Beta", 200)); // Declare an iterator to a map<string, itr>. map<string, int>::iterator itr; // Declare a reverse iterator to a map<string, itr>. map<string, int>::reverse_iterator ritr; // Find an element given its key. itr = m.find("Beta"); if(itr != m.end()) cout << itr->first << " has the value " << itr->second << "\n\n"; else cout << "Key not found.\n\n"; return 0; } // Display the contents of a map<string, int> by using // an iterator. void show(const char *msg, map<string, int> mp) { map<string, int>::iterator itr; cout << msg << endl; for(itr=mp.begin(); itr != mp.end(); ++itr) cout << " " << itr->first << ", " << itr->second << endl; cout << endl; }