ATL / WTL / STL

• What compiler you're using
• What you expect the code to do
• What actually DOES happen

followait wrote:

I use VC9, and want to do just as you said, but it throws an excetpion.

<code></code>try {
std::string a, b;
infile>>a>>b;
}
catch(std::exception&e)
{
std::cerr << e.what() << std::endl;
}

#include <iostream>
#include <fstream>
#include <string>

int main(int, char**)
{
    std::ifstream f("a.a");
    std::string a, b;
    
    f >> a >> b;
    
    std:: cout << "a = \"" << a << "\"\n";
    std:: cout << "b = \"" << b << "\"\n";
}

string_a string_b

a = "string_a"
b = "string_b"

Removes duplicate elements that are adjacent to each other in a specified range.

#include <set>
#include <vector>
#include <iostream>
#include <iterator>

struct Finder : std::unary_function<bool, int>
{
  Finder(std::set<int>& s) : s_(s) {}
  bool operator()(int i) const
  { 
    if (s_.count(i)==0)
    {
      s_.insert(i);
      return false;
    }
    else
    {
      return true;
    }
  }
  std::set<int>& s_;
};

int main(int, char**)
{
  std::vector<int> data;
  data.push_back(1);
  data.push_back(3);
  data.push_back(2);
  data.push_back(1);
  data.push_back(5);
  data.push_back(1);

  // Show the vector
  std::copy(data.begin(), data.end(), std::ostream_iterator<int>(std::cout, ", ")); std::cout << std::endl;
  
  // Use Finder and a set to remove items if we've seen them before in the vector
  std::set<int> uniqueItems;
  data.erase(std::remove_if(data.begin(), data.end(), Finder(uniqueItems)), data.end());

  // Show the vector with duplicates removed
  std::copy(data.begin(), data.end(), std::ostream_iterator<int>(std::cout, ", ")); std::cout << std::endl;
  return 0;
}

Stuart Dootson wrote:

struct Finder : std::unary_function<bool, int>

struct Finder : std::unary_function<int, bool>

// TEMPLATE STRUCT unary_function
template<class _A, class _R>
	struct unary_function {
	typedef _A argument_type;
	typedef _R result_type;
	};

// VanillaConsole.cpp : Defines the entry point for the console application.
//
 
#include "stdafx.h"
#include <iostream>
#include <vector>
#include <algorithm>
#include <iterator>
 
void main()
{
	using namespace std;
 
	// Create a vector and fill it with data.
	typedef vector<int> data_t;
	data_t data;
	data.push_back(1);
	data.push_back(3);
	data.push_back(2);
	data.push_back(1);
	data.push_back(5);
	data.push_back(1);
 
	// Show the user the contents before messing with it.
	cout << "Contents before:" << endl;
	copy(data.begin(), data.end(), ostream_iterator<int>(cout, " "));
	cout << endl << endl;
 
	// Remove the duplicates.
	sort(data.begin(), data.end());
	data_t::iterator new_end = unique(data.begin(), data.end());
 
	// Show the user the contents with duplicates removed (and sorted).
	cout < "Contents after:" < endl;
	copy(data.begin(), new_end, ostream_iterator<int>(cout, " "));
	cout << endl << endl;
}

If the order of elements is unimportant, sort the vector (with std::sort) before using unique.

#include <map>
class MyObject
{
...
   int UniqueID() const;
...
};
std::map<int, MyObject> myMap;

To insert an item:
   MyObject o;
   myMap.insert(std::make_pair(o.UniqueID(), o));
To retrieve an item:
  MyObject anotherO = myMap[someID];