Look this code(and forgive the miss of knowlegde).It outputs errors that I couldnot solve.I need to declare a vector of elements of struct C,but I need the number of elements be i(a input of type int).I also tried others aproachs but in all of them I recieved an error(cannot convert C to int,etc).How can I do this?
# include < iostream...
I have a vector of myObjects in global scope.
std::vector<myObject>
A method is passed a pointer to one of the elements in the vector.
Can this method increment the pointer, to get to the next element,
myObject* pmObj;
++pmObj; // the next element ??
or should it be passed an std::Vector<myObject>::iterator and increment that ins...
Hello all,
For a program of mine I made a small function to clear the various std::vectors of pointers that I have.
template <class S>
void clearPtrVector(std::vector<S*> &a,int size)
{
for(size_t i = 0; i < size; i++)
delete a[i];
a.clear();
}
I must have done something wrong here though since when calling this fun...
Hi all
I want a std::vector to contain some functions, and that more functions can be added to it in realtime. All the functions will have a prototype like this:
void name(SDL_Event *event);
I know how to make an array of functions, but how do I make a std::vector of functions? I've tried this:
std::vector<( *)( SDL_Event *)> functio...
Hi,
I've a class named Contact and I want to build a data structure of pointers to those objects like a matrix of 127 rows and 20 columns.
I've tried to use the std::vector class in this way
std::vector < std::vector<Contact* > > matrix (127, std::vector < Contact* > (20));
then, having declarated the following in the header
std::ve...
I am unclear about the following.
First, this code compiles fine:
#include <vector>
typedef struct{
int x1,x2,x3,x4;
} ints;
typedef std::vector<ints> vec;
int main(){
vec v;
ints a = {0,1,2,3};
v.push_back(a);
}
The following code is near identical:
#include <vector>
typedef std::vector<int[4]> vec;
int main(){
vec v;
i...
I have a standard vector of pointers.
Under what circumstances might an iterator into this vector become invalidated?
I have reason to believe that when an object is deleted, any vector iterator referencing it is thereby invalidated. This does not seem correct to me, however. I do believe this would be the standard behavior of containe...
I have four std::vector containers that all might (or might not) contain elements. I want to determine which of them has the most elements and use it subsequently.
I tried to create a std::map with their respective sizes as keys and references to those containers as values. Then I applied std::max on the size() of each vector to figure ...
Hello Gurus,
Yesterday evening I was using std::vector for my work, and this question popped into my mind: how does vector gives random access?
I tried to look into code but was unsuccessful. Can anyone give some pointers?
Thanks,
Arun
...
Is there a way to transfer ownership of the data contained in a std::vector (pointed to by, say T*data) into another construct, preventing having "data" become a dangling pointer after the vector goes out of scope?
EDIT: I DON'T WANT TO COPY THE DATA (which would be an easy but ineffective solution).
Specifically, I'd like to have some...
I would like to be able to convert between std::vector and its underlying C array int* without explicitly copying the data.
Does std::vector provide access to the underlying C array? I am looking for something like this
vector<int> v (4,100)
int* pv = v.c_array();
EDIT:
Also, is it possible to do the converse, i.e. how would I ini...
inline void add(const DataStruct& rhs) {
using namespace boost::assign;
vec.reserve(vec.size() + 3);
vec += rhs.a, rhs.b, rhs.c;
}
The above function was executed for about 17000 times and it performed (as far as I can see. There was some transformation involved) about 2 magnitudes worse with the call to vector::reserve.
I ...
I have an object that I want to travel in a continuous loop in a game. I have a series of coordinates in a std::vector that I want to use as waypoints.
Is there anyway to make an std::vector::iterator cyclic?
The best I can come up with is to have two iterators and then whenever the first iterator is exhausted assign to it the value of...
Hi,
I have a buffer class in my C++ application as follows:
class Buffer
{
public:
Buffer(size_t res): _rpos(0), _wpos(0)
{
_storage.reserve(res);
}
protected:
size_t _rpos, _wpos;
std::vector<uint8> _storage;
}
Sometimes using the constructor fails because its unable to allocate the required memory ...
I was looking through the std::vector code and I found something I didn't quite get. When capacity < size() + 1 it needs to reallocate the buffer so it can insert the new element. What it does (as far as I've been able to extract from the code) is:
allocate the new buffer
copy the prefix of the old buffer (0 - index of insertion)
const...
I can create an array initialized with elements like this:
int a[] = {10, 20, 30};
How do I create an STL vector and initialize it like the above? What is the best way to do so with the minimum typing effort?
The best I can do is:
std::vector<int> ints;
ints.push_back(10);
ints.push_back(20);
ints.push_back(30);
Though I could sh...
After a lot of investigations with valgrind, I've made the conclusion that std::vector makes a copy of an object you want to push_back.
Is that really true ? A vector cannot keep a reference or a pointer of an object without a copy ?!
Thanks
...
I have a weird problem. I have a vector that I would like to push objects on to like so:
vector<DEMData>* dems = new vector<DEMData>();
DEMData* demData = new DEMData();
// Build DEMDATA
dems->push_back(*demData);
There will be a few hundred DEMData objects in the vector. The problem is when this code is finished, all items are equ...
std::vector<Foo> vec;
Foo foo(...);
assert(vec.size() == 0);
vec.reserve(100); // I've reserved 100 elems
vec[50] = foo; // but I haven't initialized any of them
// so am I assigning into uninitialized memory?
Is the above code safe?
...
Hi,
I am new to Emacs, and
I have the following code as a sample.
I have installed GNU Emacs 23.1.1 (i386-mingw-nt6.1.7600), installed cedet-1.0pre7.tar.gz. , installed ELPA, and company.
You can find my simple Emacs configuration at the bottom.
The problem is, when I type q[0] in main() and press . (dot), I see the 37 members of the ...