I have a class (foo) that contains a vector. If i try iterating over the elements in the vector like so: for(vector<random>::iterator it = foo.getVector().begin(); it != foo.getVector().end(); ++it) { cout << (*it) << endl; } The first element is always corrupted and returns garbage data. However, if do something like: ...
Is there a C/C++/STL/Boost clean method to convert a date time string to epoch time (in seconds)? yyyy:mm:dd hh:mm:ss ...
Let's say I have a sequential container, and a range (pair of iterators) within that container of elements that are currently 'active'. At some point, I calculate a new range of elements that should be active, which may overlap the previous range. I want to then iterate over the elements that were in the old active range but that are not...
Confusing title, hopefully some code will clarify: struct MyNestedType { void func(); }; struct MyType { MyNestedType* nested; } std::vector<MyType> vec; // ... populate vec // I want something approximating this line, but that doesn't use made-up C++! std::for_each(vec.begin(), vec.end(), std::mem_fun_ref(&MyType::nested->f...
I have just found out that when I search a map like : std::map<std::string, int> aMap; the keys I search start to be part of the map. In the case above the values are stored as zeros. In case of pointers it stores the values as 0 valued pointers I am doing the search with the [] operator, like in : int a = aMap["some key"]; Ca...
In this chunk of code I add a pair on a map and everything is fine but when I delete a pair that isn't the last one the map doesn't add any more pairs. What I'm Doing wrong?? SomeClass::add(Object object) if (!object.empty()) { ObjectList::iterator result = find(object.name()); if (result == ObjectList.end()) { object.orde...
I want to find the first item in a sorted vector that has a field less than some value x. I need to supply a compare function that compares 'x' with the internal value in MyClass but I can't work out the function declaration. Can't I simply overload '<' but how do I do this when the args are '&MyClass' and 'float' ? float x; std::vect...
I have implemented this code, but fail at compilation (VC2008 Express Ed.) : Now all code is here. #include <stdio.h> #include <vector> #include <string> #include <hash_map> using namespace std; using namespace stdext; typedef vector type_key; int main(int argc, char* argv[]) { type_key key; hash_map<type_key, string> map_s...
If I have a std::vector and I want to delete the x'th element how to do it? std::vector<int> vec; vec.push_back(6); vec.push_back(-17); vec.push_back(12); vec.erase(???); Please help! ...
While reading the answers to this question I got a doubt regarding the default construction of the objects in the vector. To test it I wrote the following test code: struct Test { int m_n; Test(); Test(const Test& t); Test& operator=(const Test& t); }; Test::Test() : m_n(0) { } Test::Test(const Test& t) { m_n =...
Hey all, ok, so I got a doubt, I want to know if this is possible: I'm using a database, with generic data (strings, ints, bools, etc...). Whenever an object is constructed or a member of an object is modified, I have to query the database with the specific action (SELECT or UPDATE). First of all, this isn't a DB related question, my r...
I am running a simulation with a lot if bunch of initial memory allocations per object. The simulation has to run as quickly as possible, but the speed of allocation is not important. I am not concerned with deallocation. Ideally, the allocator will place everything in a contiguous block of memory. (I think this is sometimes called a...
I have 8 sorted lists that I need to merge into 1 sorted list. I don't know the best way to do this. I was thinking of the following: void merge_lists_inplace(list<int>& l1, const list<int>& l2) { list<int>::iterator end_it = l1.end(); --end_it; copy(l2.begin(), l2.end(), back_inserter(l1)); ++end_it; inplace_merge(l...
I can do: map<char*, int> counter; ++counter["apple"]; But when I do: --counter["apple"] // when counter["apple"] ==2; I got debugger hung up in VS 2008. Any hints? ...
Dears, Is there a way finding largest container inside a container using STL? ATM, I have this rather naïve way of doing it: int main() { std::vector<std::vector<int> > v; ... unsigned int h = 0; for (std::vector<std::vector<int> >::iterator i = v.begin(); i != v.end(); ++i) { if (*i...
Hi, I'm using std::map to store a lot of elements (pairs of elements) and I have a "little" doubt, what is more efficient to iterate all elements over my std::map, iterator or reverse_iterator? Thank's. Salu2. ...
Hi, I've got a very simple map : std::map<int, double> distances; distances[20.5] = 1; distances[19] = 2; distances[24] = 3; How do i know if there isn't any returned value, when using a map::upper_bound() in this case for example: std::map<int, double>::iterator iter = distances.upper_bound(24); (24 is the max key so an unexpecte...
I have a C++ std::vector denoted as: std::vector<GameObject*> vectorToSort; Each object in vectorToSort contains a float parameter which is returned by calling "DistanceFromCamera()": vectorToSort.at(position)->DistanceFromCamera(); I wish to sort the vector by this float parameter however std::sort does not appear to be able to do...
Something that takes 1 second to run on Linux takes 45 seconds to run on AIX. I haven't dug directly into that code but as a test grabbed a small application that does very little from another SO question: int main ( int argc, char **argv) { int i = 0; std::vector<int> vec; vec.push_back(6); vec.push_back(-17); vec.push_back(12); for ...
This is quite strange for me, but I'm getting an unexpected and random segmentation fault when I launch my program. Some times it works, some times it crashes.. The debugger of Dev-C++ points me to a line of the file : stl_construct.h /** * @if maint * Constructs an object in existing memory by invoking an allocated * object's ...