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
3
votes
2 answers
vector::push_back vs vector::operator[]
Below in c++ program,
include
#include
using namespace std;
int main()
{
vector numbers;
numbers.push_back(2);
numbers.push_back(10);
numbers.push_back(5);
numbers.push_back(3);
…
Eight
- 4,194
- 5
- 30
- 51
3
votes
1 answer
Memory error: free(): invalid next size (fast)
I'm trying to implement a radix sort, and this code produce a memory failure:
(free(): invalid next size (fast))
The code is the following:
unsigned int * radix(unsigned int *x,int n, int g,bool verbose)
{
int elem_size = sizeof(unsigned…
RSFalcon7
- 2,241
- 6
- 34
- 55
2
votes
3 answers
How to push_back to subvector?
I have a vector< vector > and want to add a string to the inside vector with push_back(). This is what I tried:
vector< vector > sorted_word_vecs;
char word_read[MAX_WORD_LENGTH];
for(int i = 0; i < num_of_pipes; i++)
{
while…
Marty
- 5,926
- 9
- 53
- 91
2
votes
1 answer
Store data in a vector from another class
I have a vector orderQueue that is stored in a class called OrderFood and a function called processUserOption in another class called MerkelMain. I am trying to get processUserOption to store orders in that orderQueue vector using the push_back…
ahmadalibin
- 133
- 8
2
votes
2 answers
vector and push_back()
#include
#include
#include
class my {
public:
my() {
counter++;
std::cout << "class constructor" << counter << " \n";}
~my() {
std::cout << "class destructor" << counter << " \n";
…
GregK1
- 21
- 2
2
votes
2 answers
How to ensure a std::vector will not be re-allocated?
I know that when using push_back() on a vector, it is possible that that vector will be re-allocated (if there is no space left) to have more space.
When using pop_back(), can the vector be re-allocated, in order to free unused space?
In general,…
Yahav
- 211
- 3
- 4
2
votes
5 answers
Operation of push_back on an element of Vector (C++)
I am a Python programmer trying to develop C++ proficiency. I have a silly question about vectors.
Suppose I have a vector like this
vector adj;
Assume it contains some values. What does this operation do ?
adj[v].push_back(w)
Does it create…
sol0invictus
- 23
- 4
2
votes
1 answer
What's the difference between the following ways of adding elements to a c++ vector
Snippet1: The following snippet prints out 0 1 but returns an empty vector.
vector trial() {
vector ret;
ret.reserve(2);
ret[0] = 0;
ret[1] = 1;
cout << ret[0] << " " << ret[1] << "\n";
return ret;
}
Snippet 2:…
user3828311
- 907
- 4
- 11
- 20
2
votes
1 answer
Vector empty Push_back calls for expected primary-expression before '{' token
im having trouble with my compiler
Im using codeblocks with gnugcc
and i want to do:
table.push_back({""});
and it says
main.cpp|22|error: expected primary-expression before '{' token|
code works in VS and other compilers... What the…
Gadzin
- 73
- 7
2
votes
1 answer
does thrust::device_vector.pushback() cause a call to memcpy?
Summary
I'd like some clarification on how the thrust::device_vector works.
AFAIK, writing to an indexed location such as device_vector[i] = 7 is implemented by the host, and therefore causes a call to memcpy. Does device_vector.push_back(7) also…
John Mansell
- 624
- 5
- 16
2
votes
1 answer
Vector of class not storing separate Textures
I'm creating a car simulation using SFML.
As a matter of organization and logic, I created a single class "car", which also inherits sf::RectangleShape, and within this class there are other SFML objects, among them a Texture and a method to setup…
Rogério Dec
- 801
- 8
- 31
2
votes
3 answers
Why is it unsafe to call push_back in a for loop even when there is no memory reallocation?
When I read this post: https://stackoverflow.com/a/42448319/3336423
I understand, that calling push_back in a for loop is unsafe because:
If the new size() is greater than capacity() then all iterators and
references (including the past-the-end…
jpo38
- 20,821
- 10
- 70
- 151
2
votes
2 answers
Why cant you push_back in 2D vector? c++
I am learning recursion in c++ and was stuck on why you cant simply use the .push_back() instead of creating a function to copy the specific_previous_result elements, then .push_back().
vector> get_every_n_elements(vector arr, int…
javiercaudillo10
- 53
- 1
- 6
2
votes
2 answers
Why vector hold a class type will call the copy constructor one more time when push_back()?
I have the following code:
#include
using std::cin; using std::cout; using std::endl;
#include
using std::vector;
class Quote {
public:
Quote() = default;
Quote(const std::string &book, double sales_price):
…
zhenguoli
- 2,268
- 1
- 14
- 31
2
votes
1 answer
How can I distinguish my characters in a vector? SFML 2.4.1
I am using push_back to add identical characters and for some reason these characters all have the same stats all the time.
Battle.cpp:
void Battle::InitalizeUser()
{
user.t_Pokemon.clear();
user.t_Item.clear();
user.currentPokemon_U…
MrFreeze
- 23
- 5