Is there any method? My computer is AMD64, ::std::string str; BOOL loadU(const wchar_t* lpszPathName, int flag = 0); when I used: loadU(&str); the VS2005 compiler says: Error 7 error C2664:: cannot convert parameter 1 from 'std::string *__w64 ' to 'const wchar_t *' How can I do it ? ...
If you have an STL vector which has been resized, is it safe to take the address of element 0 and assume the rest of the vector will follow in memory? e.g. vector<char> vc(100); // do some stuff with vc vc.resize(200); char* p = &vc[0]; // do stuff with *p ...
Multimap essentially has groups of data sorted by the key. I want a method by which I could access these individual groups and get their aggregate values. For example, in a std::multimap< string, int > I store {"Group1", 1}, {"Group1", 2}, {"Group1", 3}, {"Group2", 10}, {"Group2", 11}, {"Group2", 12} Having stored these values, ...
Hi everybody, I need to store my class A objects in some data structure. In addition, i would like them to be automatically sorted according to a key, which is in my case an embedded object of another class B. Thus I decided to use a STL priority queue. However it is possible that the 2 or more objects B to have the same key value. ...
I want to examine the contents of a std::vector in GDB, how do I do it? Let's say it's a std::vector<int> for the sake of simplicity. ...
Is there a way to resize a std::vector to lower capacity when I no longer need previously reserved space? ...
Is std::string size() a O(1) operation? The implementation of STL I'm using is the one built into VC++ ...
I'm using an std::map (VC++ implementation) and it's a little slow for lookups via the map's find method. The key type is an std::string. Can I increase the performance of this std::map lookup via a custom key compare override for the map? For example, maybe std::string < compare doesn't take into consideration a simple string::size()...
One of the things that seems to be necessary with use of STL is a way to specify local functions. Many of the functions that I would normally provide cannot be created using STL function object creation tools ( eg bind ), I have to hand roll my function object. Since the C++ standard forbids local types to be used as arguments in templa...
I wrote a C++ project in VS2005, and used lots of STL container with its plus-in STL. However, I found STL in VS2005 does not have a hash_map in it, I want to use SGI hash_map. How can I change my project to use SGI STL? Thanks for Brian's method, it works! And it's simple. ...
I want to find in a vector of Object pointers for a matching object. Here's a sample code to illustrate my problem: class A { public: A(string a):_a(a) {} bool operator==(const A& p) { return p._a == _a; } private: string _a; }; vector<A*> va; va.push_back(new A("one")); va.push_back(new A("two")); va.push_b...
I have an array of values that is passed to my function from a different part of the program that I need to store for later processing. Since I don't know how many times my function will be called before it is time to process the data, I need a dynamic storage structure, so I chose a std::vector. I don't want to have to do the standard...
I need to write the content of a map (key is ID of int, value is of self-defined struct) into a file, and load it from the file later on. Can I do it in MFC with CArchive? Thank you! ...
If I declare a temporary auto deleted character buffer using std::auto_ptr<char> buffer(new char[n]); then the buffer is automatically deleted when the buffer goes out of scope. I would assume that the buffer is deleted using delete. However the buffer was created using new[], and so strictly speaking the buffer should be deleted usi...
I've long had a desire for an STLish container that I could place into a shared memory segment or a memory mapped file. I've considered the use of a custom allocator and placement new to place a regular STL container into a shared memory segment. (like this ddj article). The problem is that STL containers will internally have pointers t...
The following code says that passing the map as const into the operator[] method discards qualifiers: #include <iostream> #include <map> #include <string> using namespace std; class MapWrapper { public: const int &get_value(const int &key) const { return _map[key]; } private: map<int, int> _map; }; int main() { ...
In the following code I loop through a map and test if an element needs to be erased. Is it safe to erase the element and keep iterating or do I need to collect the keys in another container and do a second loop to call the erase()? map<string, SerialdMsg::SerialFunction_t>::iterator pm_it; for (pm_it = port_map.begin(); pm_it != port_...
I have some function to find a value: struct FindPredicate { FindPredicate(const SomeType& t) : _t(t) { } bool operator()(SomeType& t) { return t == _t; } private: const SomeType& _t; }; bool ContainsValue(std::vector<SomeType>& v, SomeType& valueToFind) { return find_if(v.begin(), v.end(), FindPredicate...
Are there any drawbacks to using the STL or templates. Are there any situations for which they are inappropriate. ...
I am writing code in VS2005 using its STL. I have one UI thread to read a vector, and a work thread to write to a vector. I use ::boost::shared_ptr as vector element. vector<shared_ptr<Class>> vec; but I find, if I manipulate the vec in both thread in the same time(I can guarantee they do not visit the same area, UI Thread always read...