Source of remove_copy_if1a.cpp


  1: //remove_copy_if1a.cpp

  3: #include <iostream>
  4: #include <vector>
  5: #include <algorithm>
  6: using namespace std;

  8: /**
  9: Determines if an integer is divisible by 3.
 10: Pre:\n n contains an integer.
 11: Post:\n Returns true if n is divisible by 3, and otherwise false.
 12: */
 13: bool isDivisibleByThree
 14: (
 15:     int n //in
 16: )
 17: {
 18:     return (n%3 == 0);
 19: }

 21: int main()
 22: {
 23:     cout << "\nThis program illustrates the use of the STL "
 24:         "remove_copy_if() algorithm\nto copy all values except those "
 25:         "satisfying a particular condition from\none vector of integers "
 26:         "to another.";
 27:     cout << "\nPress Enter to continue ... ";  cin.ignore(80, '\n');

 29:     int a1[] = {1, 2, 2, 3, 4, 5, 2, 3, 6, 7, 2, 8, 3, 9, 10, 2};
 30:     vector<int> v1(a1, a1+16);

 32:     cout << "\nHere are the sixteen values in v1:\n";
 33:     for (vector<int>::size_type i=0; i<v1.size(); i++)
 34:         cout << v1.at(i) << " ";
 35:     cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');

 37:     int a2[] = {101, 102, 103, 104, 105, 106, 107, 108,
 38:                 109, 110, 111, 112, 113, 114, 115, 116};
 39:     vector<int> v2(a2, a2+16);

 41:     cout << "\nHere are the sixteen values in v2:\n";
 42:     for (vector<int>::size_type i=0; i<v2.size(); i++)
 43:         cout << v2.at(i) << " ";
 44:     cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');

 46:     cout << "\nNow we copy all values except those that are divisible "
 47:         "\nby 3 from v1 to v2, starting at the 3rd value of v2.";
 48:     cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');

 50:     vector<int>::iterator p = remove_copy_if(v1.begin(), v1.end(),
 51:         v2.begin()+2, isDivisibleByThree);

 53:     cout << "\nHere are the revised values in v2:\n";
 54:     for (vector<int>::size_type i=0; i<v2.size(); i++)
 55:         cout << v2.at(i) << " ";
 56:     cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');

 58:     cout << "\nThe iterator returned by the algorithm is pointing at "
 59:         "the value " << *p << ".";
 60:     cout << "\nPress Enter to continue ... "; cin.ignore(80, '\n');
 61: }