Source of map12.cpp

Structures and functions

  1: //map12.cpp

  3: #include <iostream>
  4: #include <map>
  5: #include <utility>
  6: using namespace std;

  8: int main()
  9: {
 10:     cout << "\nThis program illustrates the clear() and erase() member "
 11:         "functions\nof the map interface.";
 12:     cout << "\nPress Enter to continue ... ";  cin.ignore(80, '\n');

 14:     //Create an array of pairs
 15:     pair<char, int> a[] =
 16:     {
 17:         pair<char, int>('A', 65),
 18:         pair<char, int>('B', 66),
 19:         pair<char, int>('C', 67),
 20:         pair<char, int>('D', 68),
 21:         pair<char, int>('E', 69),
 22:         pair<char, int>('F', 70),
 23:         pair<char, int>('G', 71),
 24:         pair<char, int>('H', 72),
 25:         pair<char, int>('I', 73),
 26:         pair<char, int>('J', 74)
 27:     };

 29:     cout << "\nWe begin with a map containing the following pairs:\n";
 30:     map<char, int> m(a, a+10);
 31:     map<char, int>::iterator p = m.begin();
 32:     while (p != m.end())
 33:     {
 34:         cout << p->first << " " << p->second << endl;
 35:         ++p;
 36:     }
 37:     cout << "Press Enter to continue ... ";  cin.ignore(80, '\n');

 39:     cout << "\nThen we delete any pairs having a key of F.";
 40:     cout << "\nPress Enter to continue ... ";  cin.ignore(80, '\n');

 42:     map<char, int>::size_type numberDeleted = m.erase('F');
 43:     cout << "\nThe number of deletions was " << numberDeleted << ".";
 44:     cout << "\nAnd here are the remaining contents of the map:\n";
 45:     p = m.begin();
 46:     while (p != m.end())
 47:     {
 48:         cout << p->first << " " << p->second << endl;
 49:         ++p;
 50:     }
 51:     cout << "Press Enter to continue ... ";  cin.ignore(80, '\n');

 53:     cout << "\nNext we delete any pairs having a key of T.";
 54:     cout << "\nPress Enter to continue ... ";  cin.ignore(80, '\n');

 56:     numberDeleted = m.erase('T');
 57:     cout << "\nThe number of deletions was " << numberDeleted << ".";
 58:     cout << "\nAnd here are the remaining contents of the map:\n";
 59:     p = m.begin();
 60:     while (p != m.end())
 61:     {
 62:         cout << p->first << " " << p->second << endl;
 63:         ++p;
 64:     }
 65:     cout << "Press Enter to continue ... ";  cin.ignore(80, '\n');

 67:     cout << "\nNow we delete the first pair of the map, using an iterator "
 68:         "for access.";
 69:     cout << "\nPress Enter to continue ... ";  cin.ignore(80, '\n');

 71:     m.erase(m.begin());
 72:     cout << "\nThe remaining contents of the map are now these:\n";
 73:     p = m.begin();
 74:     while (p != m.end())
 75:     {
 76:         cout << p->first << " " << p->second << endl;
 77:         ++p;
 78:     }
 79:     cout << "Press Enter to continue ... ";  cin.ignore(80, '\n');

 81:     cout << "\nFor our final deletion before clearing all the remaining "
 82:         "pairs, we delete those\npairs having keys in the range from "
 83:         "capital letter D to capital letter G.";
 84:     cout << "\nPress Enter to continue ... ";  cin.ignore(80, '\n');

 86:     m.erase(m.find('D'), m.find('H'));
 87:     cout << "\nAfter deleting this range of values, the remaining pairs "
 88:         "in the map are:\n";
 89:     p = m.begin();
 90:     while (p != m.end())
 91:     {
 92:         cout << p->first << " " << p->second << endl;
 93:         ++p;
 94:     }
 95:     cout << "Press Enter to continue ... ";  cin.ignore(80, '\n');

 97:     cout << "\nFinally, we clear all remaining values from the map.";
 98:     cout << "\nPress Enter to continue ... ";  cin.ignore(80, '\n');

100:     m.clear();
101:     if (m.empty()) cout << "\nThe map is now empty.";
102:     cout << "\nPress Enter to continue ... ";  cin.ignore(80, '\n');
103: }