is the action of adding an element at the end of a container.
push-back is the action of adding an element at the end of a container.
Questions tagged [push-back]
420 questions
2
votes
1 answer
Vector push_back of one object results in a vector of enormous size
i'm working on a project in c++, and I have a vector of objects, where I want to push_back an object on the existing vector. However, when checking the size before and after the object is added, the size goes from 0 to 12297829382473034412 which…
Scartzaw
- 21
- 2
2
votes
1 answer
Dynamically adding a row to a std::string 2d vector array
I'm trying to create a dynamic 2d std::string vector but having trouble adding the new rows:
std::vector> hops_vector;
int Hop = 0;
for (Hop = 0; Hop < RouteHops; Hop++)
{
char HopIPString[20];
HopIPString[0] = 0;
…
Dan
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2
votes
0 answers
C++11 noexcept doesn't affect "copy/move" choice in VC. Is this a VC bug?
[Effective modern C++]says,
vector::push_back will allocate new memory block when capacity is not enough，and then "copy or move" elements to the new block
Whether to choose copy or move depends on a class A's move ctor having "noexcept" or not.…
Hind Forsum
- 9,717
- 13
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- 119
2
votes
1 answer
Implementation of push_back and pop_back
I want to understand how std::vector::push_back and std::vector::pop_back create and destroy objects in an allocated memory ?
I used google and all I find is people just play with size and capacity to limit the access to the internal…
Laith
- 1,248
- 2
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2
votes
2 answers
Appending an item to a vector copies all previous items
In the following code, I would expect that the copy constructor of A is never called, as the items should be created directly at the vector with emplace_back and then the total result should be return-value-optimized.
This seems to be the case.…
Zah
- 6,394
- 1
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- 34
2
votes
2 answers
vector push_back over std::copy
I have a function which has an unordered set as a parameter . Since I am using openmp I am converting this unordered set to vector . I use a std::copy for this conversion .
//pseudo code
func( std::unorderedset s1)
begin
vector v1;
…
sameer karjatkar
- 2,017
- 4
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- 43
2
votes
2 answers
STL push_back: previous values getting modified when pushing a dynamically changing array
I am having a very strange problem with std::vector.push_back() in my CPP code. Basically, all I am doing is:
void func()
{
if(first_time_coming_here)
{
do_some_stuff();
V.push_back(Mat::zeros(3,1,CV_32FC1)); // OpenCV Mat structure
…
HighVoltage
- 722
- 7
- 25
2
votes
2 answers
Push Back in Map
Is there any possibility to use push_back() in maps?
I want to make a map < int, vector> and fill the vector in a loop with strings.
It should look something like this:
map[int] = vector.push_back(string);
Eppok
- 55
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2
votes
1 answer
Qt containers with object
When using a Qt container as Qlist, Qvector etc to hold some class (say a complex class with many data members and logics) and calling insert/append/push_back will the object added to the container be inserted to the container or it will be copied…
ClimbingLung
- 219
- 2
- 8
2
votes
2 answers
How to use vector iterators when using vector<>::push_back()
For simplicity, I'll stick to vector but I think this applies to any vector object.
If I am using a vector::iterator to keep track of some position in a vector of int's and then I use vector::push_back(), the iterator becomes…
kilgoretrout
- 3,547
- 5
- 31
- 46
2
votes
3 answers
PushbackInputStream and mark/reset
I use PushbackInputStream to look ahead the next byte in a stream (bufferedIn which is a BufferedInputStream) because I want to mark() before some value, and later to rewind prior to it using reset().
// Wrap input stream into a push back…
mins
- 6,478
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2
votes
1 answer
std::vector's push_back() causing a strange compile-time error message
My snippet of code:
void
RMWavefrontFileImporter::loadVertexIntoVector(
const std::vector lineElements,
std::vector* vertices)
{
assert(vertices);
std::unique_ptr verticeRef =…
diegoreymendez
- 1,997
- 18
- 20
2
votes
1 answer
Problems when using repeated push_back() to initialize a vector
Problems using repeated push_back() to initialize a vector
So in my program, I have a struct containing only doubles and double arrays:
struct Particle {
double x[2];
double v[2];
double pressure;
.......
};
When I initialize one of…
user2205449
- 33
- 3
2
votes
1 answer
Vector push_back causing Unhandled exception
Everything is working until the compiler tries to perform the push_back operation.
in the if condition proper values are being returned.
I have declared items as:
vector items; // inside the header file.
//inside the .cpp file
void…
Adroit
- 701
- 1
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- 18
2
votes
3 answers
C++ Vector of classes, can't push_back inside constructor of said class
So here is my problem, I want a vector of objects of a certain class that I can then pass to other classes for use.
I want the Vector to add an instance of the class within the constructor of that class. So I've set up a static vector inside the…
Louden100
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