C/C++ :: Insert Number Of Elements From One Into Another Vector Without Resizing
Dec 28, 2012
I think std::copy appears to do what I'm looking for.
I'm in need of a vector member function that would allow me to "insert" a number of elements from one vector into another vector without resizing or destroying either.
An example of what I'm wanting to do is assign the contents of two[3-5][50-54] to one[7-9][2-6]. Other than looping through both vectors using .at(), is there a way to copy this?
This would be continuous within a user controlled loop with differing elements being exchanged.
typedef vector<vector<unsigned char> > vec;
vec one(10, vector<unsigned char>(10, '1')),
two(90, vector<unsigned char>(90, '2'));
View 4 Replies
ADVERTISEMENT
Dec 1, 2013
how to insert a variable for the size of array and prompt user to insert the elements for the array?
View 13 Replies
View Related
Mar 8, 2013
Here I have given my sample code, but it gave error. How can insert value in structure vector?
struct Hough_Transform_3D_Accumulator {
long int i;
long int j;
long int k;
long int count;
[Code] ....
Error Message:error C2661: 'std::vector<_Ty>::push_back' : no overloaded function takes 4 arguments
View 5 Replies
View Related
May 3, 2013
I am storing info in a vector but I want to store certain info at a particular index. I am new to using vectors and am unsure about have to do this. I am aware of the insert method but am confused on how to use it to store at a particular index.
View 1 Replies
View Related
Mar 7, 2013
Here I have given my sample code, but it gave error. How can insert value in structure vector?
Code:
struct Hough_Transform_3D_Accumulator {
long int i;
long int j;
long int k;
long int count;
[code].....
Error Message:error C2661: 'std::vector<_Ty>:ush_back' : no overloaded function takes 4 arguments
View 3 Replies
View Related
Nov 30, 2013
I would like to insert some character after each number of my string .. I found how to insert before each character, but what I want is :
string str = "12 + 5"
insert ^ after each number
Output = "12^ + 5^"
View 7 Replies
View Related
Mar 21, 2013
I'm writing a program with a class containing a private std::vector<bool>. I chose bool because the vector represents a 2D array (think grid) and I only need 2 states per cell. I kept it one-dimensional as this hardly complicates things.
My problem is that I don't know how to initialize the vector, i.e. fill it with 0's.
The grid's resolution is not known at compile time, so I imagine I have to set the size (and content) of the vector in the class constructor.
Here's what I have tried among several things:
Code: World::World(const u_short worldsize)
{
grid.reserve(worldsize * worldsize); // grid is the private vector; square dimensions.
std::fill(grid.begin(), grid.end(), 0);
std::cout << grid.size();
} The output is 0. Only std::vector::push_back seems to have an effect on size(), but judging by its description, it doesn't look like the right candidate to populate a vector with zeros. Correct me if I'm wrong.
Frankly I expected line 3 to set the vector's size.
View 5 Replies
View Related
Apr 21, 2014
how to swap the first and 'mid' elements of a vector?
View 2 Replies
View Related
Feb 14, 2013
I have an integer vector of size "n".
e.g.
std::vector<int> vec;
vec.pushback(0);
vec.pushback(1);
vec.pushback(2);
vec.pushback(3);
Now I want to generate all possible combinations of size = {0, 1, 2, ... , n}.
{0, 1, 3} is not equal to {3, 1, 0} or {1, 0, 3} or {3, 0, 1}
View 7 Replies
View Related
Apr 9, 2014
I had a question about memory allocation/how iterators work for a std::vector<foo> of a user defined class 'foo'. Say foo contains variables of variable size, so that each member of the std::vector<foo> does not require the same amount of memory space.
Does c++ allocate the same amount of memory for each element, equal to the amount of memory required for the largest element? Or does it use some sort of array of pointers pointing to the location of each element in the vector to make the iterator work? Or does it use some other method? I am wondering because I wrote a code which reads data from a binary files and stores most of it in std::vectors.
The code seems to be using significantly more memory than the sum of the size of all the binary files, and I am using vectors made up of the datatype within the binary files (float). So I was wondering if internally the code was allocating space for each vector element which is the size of the largest element as a way to handle indexing/iterators. I ran my code through a memory leak checker and it found no errors.
View 16 Replies
View Related
May 5, 2013
I am currently trying to implement a 2d vector to store x and y of type int.
I have successfully passed it to the function, however i am unable to store the values in it. It always returns with a segmentation fault and my program terminates from there. May i know how do i store them properly and call them out?
Below is my code snippet
int reconstructSecret(int x, int y, vector< vector<int> > &inVec ,int constructSecret) {
int getX,getY,formula,accum,count,getSecret,startPosition,nextPosition,numerator,denominator;
getX=x;
getY=y;
int result;
[Code] .....
The main method
vector< vector<int> > inVec;
for(int i=0;i<constructSecret;i++) {
cout<<"please key in the "<<i<< "share of x value:";
cin>>x;
[Code] ...
View 9 Replies
View Related
Mar 23, 2015
I am working on a project for class where I use a parent Shape class with circle, rectangle, ect. Classes inheriting from that. Along side these I use a class called Scene. In main I need to create a scene and add some shapes to a vector in scene.
vector<Shape*> shapes
I need to use functions addShape(Shape* shape) and a delete shape method. I have the addShape finished. The problem I am having is with the delete method. Is there a way that I can use something like deleteShape(Shape* shape)? Is it possible for me to delete a specific shape from the vector by passing in that shape, or can it only be done using index? I have looked at the documentation for std::vector as well as std::vector::erase. I am wondering this because if I use index values and do something like
void Scene::deleteShape(unsigned int x) { shapes.erase(shapes.begin() + x ); }
It will lead to some errors later on due the the changing size and indexes of the vector and elements.
View 4 Replies
View Related
May 1, 2015
so lets assume i have a nested vector in a set or vice versa o in a more general form a container in a container example...
Code:
std::set<vector<int> > my_tuple;
How do i access individual elements of lets say the first vector in the set! Or the last element in the 3rd vector?
View 7 Replies
View Related
Oct 7, 2014
here is a piece of my code:
while(T--)
{
std::vector<std::pair<int, int> > *dragon;
std::vector<std::pair<int, int> > *villager;
[Code]....
I now wish to print the elements of the vector. How do I do it?
View 2 Replies
View Related
Mar 30, 2013
"Write a declaration for a function that takes two int parameters and returns an int, and declare a vector whose elements have this function pointer type."
View 9 Replies
View Related
Jul 19, 2013
I have read that the Erase-remove idiom is the way to go. I have a rough understanding of how this works but am unsure whether I can implement a match-counter along with it.
For counting alone, I would use something like this:
Code:
std::vector<std::string> v; // contains duplicate strings in different elements
std::string term = "foo"; // search term, changing at runtime as well
unsigned int matches = 0;
for( auto e : v ) {
if( e == term ) {
[Code] .....
I'm not sure how (or if) I can combine the two things. That is, I don't know how to integrate a function comparing two (changing) strings into the remove_if() method. Nor do I know how to increment a counter during iteration.
The vector is extremely large, so speed is paramount. I think there are many other avenues for optimization, but decreasing the vector's size for each consecutive search could deliver a big speed boost for subsequent searches I imagine, as traversing it holds the biggest cost.
View 3 Replies
View Related
Feb 6, 2014
In this program what i'm doing is to search for a number when the vector is in order, and count how many times that number appears, the problem is that count how many times the number does not appear, but when its appear the program stays in an "standby mode" and the cursor does not move.
int buscarNumOrdenado (int x [MAX]) //MAX is the define {
int num,d, LimiteInferior, LimiteSuperior,mitad;
d=0;
LimiteInferior = 0;
LimiteSuperior = MAX-1;
[Code] ....
View 2 Replies
View Related
Jul 26, 2014
How to get the number of elements of a multi-dimensional wstring?
The usual char array way not working.
Code:
int main()
{
wstring wstr[][255] =
{
L"bbbb",
L"bbbb",
L"aaa",
L"ccccccc"
};
int Size = wstr.size() / wstr[0].length();
}
View 11 Replies
View Related
Apr 7, 2014
I can have at most 3 structs in array, but it could be 0,1,2 or 3 structs in array. I am trying to avoid dynamic memory allocation. I initialize sensors to 3 to reserve space for them in memory, since there may be at most 3 elements in the array. But I am testing a condition where there will only be 2 elements:
Code:
#include <stdio.h>#include <stdlib.h>
#include <string.h>
typedef struct {
unsigned long long int address;
float current;
unsigned char pressure_units;
} sensor;
[Code]...
The problem is even though there are only 2 sensors out of 3 in the array, sizeof(sensors)/sizeof(sensors[0]) returns 3. I assume because when it allocates memory for 3, it includes that allocated memory even though it really doesn't contain the struct. How can I figure out how many elements were really inserted into array, not just allocated to array?
View 3 Replies
View Related
Jul 24, 2014
I am given an array with n elements but need to write a function where it returns n-1 elements. Do I need a loop for this? Or must I write a prototype...
Here is what I have thus far:
//given array with 5 elements function must return value 4 elements since -1 is a special character length of list is finite
#include <iostream>
using namespace std;
int main () {
int array [] = {1, 4, -1, 3, 2};
cout << "The array has " <<sizeof (array)/ sizeof (int)<< " elements"<< endl;
return 0;
}
View 5 Replies
View Related
Apr 10, 2014
Is it possible to have array in class without number of elements, for example: I have a class called Plane with number of motors, and string array of passengers, but I don't have a number of passengers, but then again I have it in constructor, so can i print the list of passengers without having the number as part of the class.
Class Plane
{
private:
int motors; //number of motors
[Code].....
View 8 Replies
View Related
Jul 18, 2014
I have a simple problem about memory allocation.In the function Nr_elements() i assign a value which represent the elements of array. The pointer p is initialised with the address of variable n, but when i compile i dont know why but dont work. This function return a pointer.
Code:
#include<stdio.h>
#include<stdlib.h>
int *Nr_elements();
int *allocate(int);
void deallocate(int *);
[code]....
View 3 Replies
View Related
Aug 15, 2014
Code:
#include<stdio.h>
#include<stdlib.h>
struct node{
int data;
struct node *next;
[Code] .....
View 2 Replies
View Related
Sep 10, 2013
Supposing you have a 3 or more overlapping arrays (arrays having elements in common), and you wish to select 2 or more of the arrays with the maximum number of elements but less overlap as compared to the rest of the overlapping arrays.
Eg. A[4],B[6],C[5]. A+B contains 10 elements but say the overlapping element is 3, meaning it has 7 unique element.
Also B+C=11 elements , but supposing it has 5 overlaps, it would mean it has only 6 unique elements. A+B+C=15. Supposing the overlaps are 11 then it means the unique elements are 4. Ect. So per the example, the best array options with most unique element would be A+B .
View 4 Replies
View Related
Apr 22, 2013
Why isn't this bubble sort working?
void LList :: bubbleSort (LList A, int n){
Node *temp;
temp = Head;
int hold;
for (int pass = 1; pass <= n-1; pass++) // number of passes needed for bubblesort is the number of elements-1 {
for (int c = 0; c < n-pass; c++)//only runs for unsorted elements
[Code] ....
It is passed the LList, and the number of items in the list...
View 6 Replies
View Related
Jun 14, 2014
I have a function where i declared the number of elements in a vector alocated dynamically which returns the vector to the main function. The problem is how can i find the number of elements in main function? I tried length = sizeof(a) / sizeof(int) which gives me the same value, the value of the first element. Here's the code:
int* functie2 (void)
{
int* p;
int c,i;
printf("number of elements: ");
scanf("%d",&c);
[Code]...
I know i could first read the value of c in main and then pass it thorugh parameter, but how can i do it the other way arround?I could also send the value of c allocating one more int value to the vector, but i don't want doing so.
Where's the edit button?
View 4 Replies
View Related
