It appears to from my simple testing but I'm wondering if this is guaranteed? Are there conditions where the ordering will be not be guaranteed? Edit: The case I'm particularly interested in is if I populate a map with a large number of entries, will the order of the itertator be the same across multiple runs of my executable? What if ...
i have code like this string xml_path(conf("CONFIG")); xml_path+=FILE_NAME; Where, conf function returns char * and FILE name is const char * I want to combine it to one line like xml_path(conf("CONFIG")).append(FILE_NAME) how do i do it? any suggestions ?? ...
I've setup a std map to map some numbers, at this point I know what numbers I'm mapping from an to, eg: std::map<int, int> myMap; map[1] = 2; map[2] = 4; map[3] = 6; Later however, I want to map some numbers to the lowest number possilbe that is not in the map, eg: map[4] = getLowestFreeNumberToMapTo(map); // I'd like this to return...
In a C++ program I write: #include<iostream> #include<vector> using namespace std; int main() { vector<int> a; a.resize(1); for( int i = 0 ; i < 10 ; i++ ) { cout << a[i] << " "; } return 0; } this program prints the correct value of a[0] (because it is allocated) but also prints values at the rest of the 10 lo...
What exactly must I replace ??? with to get the iterator (it) to some element (for example Base(2)) ? I tried a few shots but nothing, compiler just says that it is wrong. Here is code #include <cstdlib> #include <iostream> #include <vector> using namespace std; class Base { public: Base(int a) {ina = a;} ~Base() {} ...
I have a function that reads lines from a log file, converts these lines to a certain class and returns a STL list of instances of this class. My question is: how should I declare this function so that the whole list is NOT copied when attributing it to the caller? Without loss of generality, assume: list<Request> requests = log_manipu...
I see this in the standard C++ libraries for my system, as well as some of the headers in a library I'm using. What are the semantics of these two definitions? Is there a good reference for #defines like this other than the source itself? ...
When is using a std::set more efficient (w.r.t. time) than using a std::vector along with make_heap/push_/pop_ for the priority queue in an A* operation? My guess is that if the vertices in the open list are small, using a vector is a better option. But does anyone have experience with this? ...
I'm having some trouble in declaring a STL Set of pointers to class instances. More specifically, I have this scenario: class SimulatedDiskFile { private: // ... public: // ... struct comparator { bool operator () (SimulatedDiskFile* const& file_1, SimulatedDiskFile* const& file_2) { return ((*file_1)->getF...
Hi Guys I want to know what is the difference between thread safe Data and Thread Safe Containers ...
Hi all! I have the following functor: class ComparatorClass { public: bool operator () (SimulatedDiskFile * file_1, SimulatedDiskFile * file_2) { string file_1_name = file_1->getFileName(); string file_2_name = file_2->getFileName(); cout << file_1_name << " and " << file_2_name << ": "; if (file_1_name <...
I was wondering why the vector templates perform two allocations, when only one seems to be necessary. For example this: #include <vector> #include <iostream> class A { public: A(const A &a) { std::cout << "Calling copy constructor " << this << " " << &a << "\n"; } A() { std::cout ...
Let's say I have a CString variable carrying the string "Bob Evans". I want to copy from position 4 until the end of the original CString to a new CString, but I am having trouble finding semantics examples for this: CString original("Bob Evans"); // Below is what I'm trying to do // CString newStr = original.copy(4, original.GetLength(...
I have a list iterator that goes through a list and removes all the even numbers. I can use the list iterator to print out the numbers fine but I cannot use the list's remove() and pass in the dereferenced iterator. I noticed that when the remove() statement is in effect, *itr gets corrupted? Can somebody explain this? #include <iostre...
I'm writing a little Python extension in C/C++, and I've got a function like this: void set_parameters(int first_param, std::list<double> param_list) { //do stuff } I'd like to be able to call it from Python like this: set_parameters(f_param, [1.0, 0.5, 2.1]) Is there a reasonably easy way to make that conversion? Ideally, I'd ...
If the value of an element in a set changes the ordering may be no longer correct. As illustrated in this little program: #include <algorithm> #include <iostream> #include <set> #include <string> struct Comp { bool operator()(const std::string * lhs, const std::string * rhs) { return *lhs < *rhs; } }; int main() { ...
How does STL algorithm work independent of Iterator type? ...
std::string str; std::stringstream strm(str); I get this error: Error 11 error C2248: 'std::basic_ios<_Elem,_Traits>::basic_ios' : cannot access private member declared in class 'std::basic_ios<_Elem,_Traits>' c:\program files\microsoft visual studio 9.0\vc\include\sstream 517 If I use istringstream, same happens...
I am developing a program where I find myself doing this like this a lot: void Model::SetCollideMode( const std::string &m ) { Body *body; std::map<std::string, Body* >::iterator iter; for (iter=this->bodies.begin(); iter!=this->bodies.end(); iter++) { body = iter->second; body->SetCollideMode( m ); } } I have sev...
Lets say I have hierarchy like this (This is just a test program. Please do not point anything related to memory leaks, destructor is not virtual etc): class I { public: virtual void fun(int n, int n1) = 0; }; class A : public I { public: void fun(int n, int n1) { std::cout<<"A::fun():" <<n<<" and n1:" <<n1<<"\n"; ...