ATL / WTL / STL

bob16972 wrote:

How do I set the initial size and grow by values for vector

std::vector<int> vec;
vec.reserve(3);
vec.push_back(1);
vec.push_back(2);
vec.push_back(3);

#include <iostream>
#include <vector>

int main(int, char**)
{
   std::vector<int> a;

   size_t cap = a.capacity();
   for(int i =0;i<100000000;++i)
   {
      a.push_back(i);
      if (cap != a.capacity())
      {
         cap = a.capacity();
         std::cout << "Reallocation! -> " << cap << " elements\n";
      }
   }
}

Reallocation! -> 1 elements
Reallocation! -> 2 elements
Reallocation! -> 3 elements
Reallocation! -> 4 elements
Reallocation! -> 6 elements
Reallocation! -> 9 elements
Reallocation! -> 13 elements
Reallocation! -> 19 elements
Reallocation! -> 28 elements
Reallocation! -> 42 elements
Reallocation! -> 63 elements
Reallocation! -> 94 elements
Reallocation! -> 141 elements
Reallocation! -> 211 elements
Reallocation! -> 316 elements
Reallocation! -> 474 elements
Reallocation! -> 711 elements
Reallocation! -> 1066 elements
Reallocation! -> 1599 elements
Reallocation! -> 2398 elements
Reallocation! -> 3597 elements
Reallocation! -> 5395 elements
Reallocation! -> 8092 elements
Reallocation! -> 12138 elements
Reallocation! -> 18207 elements
Reallocation! -> 27310 elements
Reallocation! -> 40965 elements
Reallocation! -> 61447 elements
Reallocation! -> 92170 elements
Reallocation! -> 138255 elements
Reallocation! -> 207382 elements
Reallocation! -> 311073 elements
Reallocation! -> 466609 elements
Reallocation! -> 699913 elements
Reallocation! -> 1049869 elements
Reallocation! -> 1574803 elements
Reallocation! -> 2362204 elements
Reallocation! -> 3543306 elements
Reallocation! -> 5314959 elements
Reallocation! -> 7972438 elements
Reallocation! -> 11958657 elements
Reallocation! -> 17937985 elements
Reallocation! -> 26906977 elements
Reallocation! -> 40360465 elements
Reallocation! -> 60540697 elements
Reallocation! -> 90811045 elements
Reallocation! -> 136216567 elements

Stuart Dootson wrote:

If it is a reasonably good approximation, then an extra 50% should be sufficient for any overflow?

Stuart Dootson wrote:

You might also want to investigate std::deque - this allocates storage as a linked list of blocks, meaning that new allocations don't require relocation of existing elements.

Stuart Dootson wrote:

As for GrowBy - you're out of luck there

Zac Howland wrote:

All the memory for a deque is contiguous

#include <deque>
#include <iostream>

int main(int, char**)
{
   std::deque<char> x;

   x.resize(10);
   if (&x.back()-&x.front() == std::distance(x.begin(), x.end())-1)
   {
      std::cout << "x is contiguous\n";
   }
   else
   {
      std::cout << "x is not contiguous\n";
   }

   x.resize(1e6);
   if (&x.back()-&x.front() == std::distance(x.begin(), x.end())-1)
   {
      std::cout << "x is contiguous\n";
   }
   else
   {
      std::cout << "x is not contiguous\n";
   }
}

x with 10 elements is contiguous
x with 1000000 elements is not contiguous

shaohao wrote:

CDoubleBufferImpl

TClarke wrote:

When I started C++ I used MFC. I found CString a doddle to use sadly it turned out to be not exactly the finest of string implementations.

TClarke wrote:

Has this been resolved in the WTL or should I stick with the STL string or lower level self made implementations?

#include <algorithm>
#include <vector>

struct Mark
{
   int mark;
   int studentCode;
};

bool operator<(Mark const& left, Mark const& right) { return left.mark < right.mark; }

int main(int, char**)
{
   std::vector<Mark> marks;
   // Populate marks
   std::sort(marks.begin(), marks.end());
}

shaohao wrote:

I want to popup a tooltip when mouse hover each control in dialog box.