// comments

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>

std::ostream& operator<<(std::ostream& out, std::vector<std::string>& v) {
  using namespace std;
  // looping on vector iterators: don't EVER use "vi < v.end()", always "vi != v.end()"
  for(vector<string>::iterator vi = v.begin(); vi != v.end(); vi++) {
    out << *vi << " ";
  }
  out << endl;
  return out;
}

int checkSum(std::string s) {
  using namespace std;
  int ret = 0;
  for(string::iterator si = s.begin(); si != s.end(); si++) {
    ret += (int) *si;
  }
  cout << "checkSum(" << s << ") = " << ret << endl;
  return ret;
}

// user-defined comparator: ALWAYS MAKE SURE IT DEFINES A STRICT ORDER!!!!
bool myComparator(std::string s, std::string t) {
  int ssize = s.size();
  int tsize = t.size();
  int n = ssize < tsize ? ssize : tsize;
  int i = 0;
  while(i < n && s[i] == t[i]) { 
    i++;
  }
  if (i < n) {
    if (s[i] > t[i]) {
      return true;
    } else {
      return false;
    }
  } else {
    return ssize > tsize;
  }
}

int main(int argc, char** argv) {
  using namespace std;
  int ret = 0;

  vector<string> cmdLineArgs;
  for(int i = 1; i < argc; i++) {
    cmdLineArgs.push_back(argv[i]);
  }
  cout << cmdLineArgs;

  for_each(cmdLineArgs.begin(), cmdLineArgs.end(), checkSum);

  vector<string> cla2(cmdLineArgs);
  for(vector<string>::iterator vi = cla2.begin(); vi != cla2.end(); vi++) {
    for(string::iterator si = vi->begin(); si != vi->end(); si++) {
      (*si)++;
    }
  }
  cout << cla2;

  // sorting with a hand-made comparator
  sort(cmdLineArgs.begin(), cmdLineArgs.end(), myComparator);
  cout << cmdLineArgs;

  // swap two iterators
  iter_swap(cmdLineArgs.begin(), cmdLineArgs.begin()+1);
  cout << cmdLineArgs;

  // find maximum element
  vector<string>::iterator theMaxEl = 
    max_element(cmdLineArgs.begin(), cmdLineArgs.end());
  cout << "maximum element = " << *theMaxEl << endl;

  // merge two sorted vectors
  sort(cmdLineArgs.begin(), cmdLineArgs.end());
  sort(cla2.begin(), cla2.end());
  vector<string> result(cmdLineArgs.size() + cla2.size());
  merge(cmdLineArgs.begin(), cmdLineArgs.end(), cla2.begin(), cla2.end(), 
	result.begin());
  cout << result;

  /* // wrong way to erase elements from a vector (risk segmentation fault)
  int k = 1;
  for(vector<string>::iterator vi = result.begin(); vi != result.end(); vi++) {
    if (k % 2 == 1) {
      result.erase(vi);
    }
  }
  cout << result;
  */

  // right way to erase elements from a vector
  int k = 1;
  vector<string>::iterator myIt = result.begin();
  while(myIt != result.end()) {
    if (k % 2 == 1) {
      myIt = result.erase(myIt);
    } else {
      myIt++;
    }
    k++;
  }
  cout << result;

  return ret;
}