C++ Tutorial/STL Algorithms Sorting/stable sort

The generic stable_sort algorithms with predicate

<source lang="cpp">#include <vector>

1. include <algorithm>
2. include <iostream>
3. include <iterator>

using namespace std; class comp_last {

public:
 bool operator()(int x, int y) const
   // Compare x and y based on their last base-10 digits:
 {
   return x  10;
 }

}; int main() {

 const int N = 20;
 vector<int> vector0;
 for (int i = 0; i < N; ++i)
  vector0.push_back(i);
 vector<int> vector1 = vector0;
 ostream_iterator<int> out(cout, " ");
 cout << "Before sorting:\n";
 copy(vector1.begin(), vector1.end(), out);
 cout << endl;
 sort(vector1.begin(), vector1.end(), comp_last());

 cout << "After sorting by last digits with sort:\n";
 copy(vector1.begin(), vector1.end(), out);
 cout << endl << endl;
 vector1 = vector0;
 cout << "Before sorting:\n";
 copy(vector1.begin(), vector1.end(), out);
 cout << endl;
 stable_sort(vector1.begin(), vector1.end(), comp_last());

 cout << "After sorting by last digits with stable_sort:\n";
 copy(vector1.begin(), vector1.end(), out);
 cout << endl << endl;
 return 0;

}</source>

Before sorting:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
After sorting by last digits with sort:
10 0 11 1 12 2 13 3 4 14 5 15 6 16 7 17 8 18 9 19
Before sorting:
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
After sorting by last digits with stable_sort:
0 10 1 11 2 12 3 13 4 14 5 15 6 16 7 17 8 18 9 19