I need to insert 10-million strings into a C++ STL set. The strings are sorted. Will I have a pathological problem if I insert the strings in sorted order? Should I randomize first? Or will the G++ STL implementation automatically rebalance for me? ...
I have a C++ class where I'm trying to use std::bind1st to bind a member function to the 'this' parameter. For example: class MyClass { public: void Foo() { using namespace std; // this works fine this->Bar(); // this also works fine mem_fun( &MyClass::Bar )( this ); // this does not ...
I was trying to write an STL method to take the log of a vector: for_each(vec.begin(),vec.end(),log); But I get no matching function for call to ‘for_each(__gnu_cxx::__normal_iterator<double*, std::vector<double, std::allocator<double> > >, __gnu_cxx::__normal_iterator<double*, std::vector<double, std::allocator<double> > >, <unres...
Im trying to implement my own Huffman Coding algorithm and the priority queue for the C++ STL does not seem to be working correctly. I am taking characters from a string and inserting them into a priority queue by order of their frequency in the string. The code compiles and runs without error, the only thing is the tree seems to not be ...
Here is what I'm trying to do: //ImageCache.h: #include <map> #include <SDL.h> typedef pair<const wchar_t*, SDL_Surface*> ImageNameAndSurface; class ImageCache { // Functions public: ImageCache(); ~ImageCache(); SDL_Surface* getImage(const wchar_t* imageFilename); // Variables private: map<const ...
Hello to everyone, I wonder if and how it is possible to define a function object inside a classes member function to use it directly with, for example, the std::transform function. I know the example is a bit stupid, it's just to show the problem I'm confronted with. File "example.h" class Example { public: //.. constructor and...
What it is? What it does? When it should be used? Good links are appreciated. ...
Hello, I have an array of precomputed integers, it's fixed size of 15M values. I need to load these values at the program start. Currently it takes up to 2 mins to load, file size is ~130MB. Is it any way to speed-up loading. I'm free to change save process as well. std::array<int, 15000000> keys; std::string config = "config.dat"; /...
I have a template class with a private map member template <typename T> class MyClass { public: MyClass(){} private: std::map<T,T> myMap; } I would like to create a private method that accepts an iterator to the map void MyFunction(std::map<T,T>::iterator &myIter){....} However, this gets a compile error: identifier 'iterat...
I'm having problems with istream_iterator reading a file because it ignores blank lines, but I need that those blank lines are included as "". How should I modify the program below to get the 5 lines in my vector? #include <sstream> #include <string> #include <iostream> #include <vector> #include <iterator> using namespace std; int ma...
I need a key in the map, however, I found it should be multiple data. Can I put these data in one user defined class and put the whole class as a key in the map? Will it impact the time efficiency? What other concerns should be applied here? ...
I implemented an iterator, which has Fibonacci numbers as output. In my main() I'd like to find a number which is dividable by 17 (it's 34). Why doesn't work my find_if statement. Thank you! #include <boost/operators.hpp> #include <algorithm> #include <tr1/functional> struct FibIter: boost::input_iterator_helper<FibIter,uns...
I understand, using srand(time(0)), helps in setting the random seed. However, the following code, stores the same set of numbers for two different lists. Wondering, how do I generate the different set of numbers when the following function gets called more than once. void storeRandomNos(std::list<int>& dataToStore) { int noofElem...
I've got a container and would like to erase elements based on a predicate. Erase_if sounds familiar, but I can't find it in C++. What's the name and where is it defined? I'd like to use it with a lambda in VS10. ...
Goal is, I've multiple lists of elements available, and I want to be able to store all of these elements into a resultant list in an ordered way. Some of the ideas that comes to my mind are a) Keep the result as a set (std::set), but the B-tree , needs to rebalanced every now and then. b) Store all the elements in a list and sort the li...
I was expecting the second assert in the following to pass. I'm asking for your help. Edit: It didn't work when I had poss everywhere instead of poss_a in some places. #include <vector> #include <cassert> class Sampler { public: std::vector<int*> poss; std::vector<int*>::const_iterator poss_it; Sampler(std::vector<int*> poss_a) : ...
Is there any way to use the += operator with a vector without using boost or using a derivated class? Eg. somevector += 1, 2, 3, 4, 5, 6, 7; would actually be somevector.push_back(1); somevector.push_back(2); somevector.push_back(3); etc. ...
Possible Duplicate: sum of elements in a std::vector I want to sum the items of a std::vector For example std::vector<int > MYvec; /*some push backs*/ int x=sum(MYVec); //it should give sum of all the items in the vector How to write sum function? I have tried this int sum(const std::vector<int> &Vec) { int res...
I have seen code which use vector, vector<int>s; s.push_back(11); s.push_back(22); s.push_back(33); s.push_back(55); for (vector<int>::iterator it = s.begin(); it!=s.end(); it++) { cout << *it << endl; } It is same as for (auto it = s.begin(); it != s.end(); it++) { cout << *it << endl; } How safe is in this case the use of...
Following an example in Accelerated C++, I created a custom STL container, which is a simplified version of std::vector, called Vec. Everything worked fine, until, emboldened by success, I tried to add a Vec::clear() that will clear the vector. Here's the latest class definition (only the relevant parts to this question): template <cl...