C++ Tutorial/STL Algorithms Iterator/reverse iterator

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reverse iterator and find

#include <algorithm>
#include <vector>
#include <iostream>
#include <iterator>
using namespace std;
int main(int argc, char** argv)
{
  vector<int> myVector;
  myVector.push_back(1);
  myVector.push_back(2);
  myVector.push_back(3);
  myVector.push_back(4);
  myVector.push_back(5);
  int num = 3;
  vector<int>::iterator it1;
  vector<int>::reverse_iterator it2;
  it1 = find(myVector.begin(), myVector.end(), num);
  it2 = find(myVector.rbegin(), myVector.rend(), num);
  if (it1 != myVector.end()) {
    cout << num << " : position " << it1 - myVector.begin() << " going forward.\n";
    cout << num << " : position " << it2.base() - 1 - myVector.begin() << " going backward.\n";
  } else {
    cout << "Failed to find " << num << endl;
  }
  return (0);
}

Use a reverse_iterator to go from the end to the beginning

#include <iostream>
#include <list>
#include <algorithm>
#include <string>
using namespace std;
static const int ARRAY_SIZE = 5;
int main( ) {
   list<string> lstStr;
   lstStr.push_back("A");
   lstStr.push_back("B");
   lstStr.push_back("C");
   lstStr.push_back("D");
   for (list<string>::iterator p = lstStr.begin( );
        p != lstStr.end( ); ++p) {
      cout << *p << endl;
   }
   for (list<string>::reverse_iterator p = lstStr.rbegin( );
        p != lstStr.rend( ); ++p) {
      cout << *p << endl;
   }
}
A
B
C
D
D
C
B
A