logo
Tags down

shadow

Copying the vector elements into std::array


By : gnad
Date : August 01 2020, 02:00 PM
This might help you I have a vector of elements of type uint8 which I am copying into one std::array. After some operations again I need to copy the elements from std::array to a vector.Please find the code below , You could copy by size of vector.
code :
#include <iostream>
#include <vector>
#include <array>
#include <cstdint>
#include <limits>
#include <algorithm>

int main()
{
    std::array<std::uint32_t, 5> elem_arr ;
    std::vector<std::uint32_t> ele_vec {1,2,3};
    std::copy(ele_vec.begin(),ele_vec.end(),elem_arr.begin());
    std::vector<std::uint32_t> ele_vec_copy { elem_arr.begin() , elem_arr.begin() + ele_vec.size() };

    for(auto ele : ele_vec_copy)
        std::cout << ele << std::endl;

    return 0;
}
#include <iostream>
#include <vector>
#include <array>
#include <cstdint>
#include <limits>
#include <algorithm>
#include <limits>

std::array<std::uint32_t, 5> elem_arr;

void copy_from_vector(std::vector<std::uint32_t> elem_vec)
{
    std::copy(elem_vec.begin(),elem_vec.end(),elem_arr.begin());
}

std::vector<std::uint32_t> copy_from_array()
{
    std::vector<std::uint32_t> ele_vec_copy;
    std::copy_if( elem_arr.begin() , elem_arr.end() , 
                  std::back_inserter( ele_vec_copy ) , 
                  []( std::uint32_t val ) { 
                      return val != std::numeric_limits<std::uint32_t>::max(); 

                  } );
    return ele_vec_copy;
}

int main()
{

    elem_arr.fill( std::numeric_limits<std::uint32_t>::max() );
    std::vector<std::uint32_t> ele_vec {1,2,3};

    copy_from_vector(ele_vec);

    auto ele_vec_copy = copy_from_array();

    for(auto ele : ele_vec_copy)
        std::cout << ele << std::endl;

    return 0;
}
#include <iostream>
#include <vector>
#include <array>
#include <cstdint>
#include <limits>
#include <algorithm>
#include <limits>
#include <optional>

std::array<std::optional<std::uint32_t>, 5> elem_arr;

void copy_from_vector(std::vector<std::uint32_t> elem_vec)
{
    std::transform( elem_vec.begin() , elem_vec.end() , 
                    elem_arr.begin() ,
                    []( auto val ) { return std::optional<std::uint32_t>{ val }; }
                   );
}

std::vector<std::uint32_t> copy_from_array()
{
    std::vector<std::uint32_t> ele_vec_copy;
    std::vector<std::optional<std::uint32_t>> non_null_elements;
    std::copy_if( elem_arr.begin() , elem_arr.end() , 
                  std::back_inserter( non_null_elements ) , 
                  []( auto val ) { 
                      return val;
                  } );
    std::transform( non_null_elements.begin(), non_null_elements.end() , 
                    std::back_inserter( ele_vec_copy ) ,
                    []( auto val ) { return *val; } 
                  );
    return ele_vec_copy;
}

int main()
{
    std::vector<std::uint32_t> ele_vec {1,2,3};

    copy_from_vector(ele_vec);

    auto ele_vec_copy = copy_from_array();

    for(auto ele : ele_vec_copy)
        std::cout << ele << std::endl;

    return 0;
}


Share : facebook icon twitter icon

Copying elements from a char vector to a string vector


By : alexflores2323
Date : March 29 2020, 07:55 AM
help you fix your problem You had to make sure that your other vector has enough elements in it.
(UPDATE: using postfix operation for v2 will save memory and running time, because in that case no temporary variable has to be allocated to perform the addition operation.)
code :
vector <string> v2(v1.size());
for(int i=0;i<=v1.size();i++){    //v1 is the char vector
    for (int j=0;j<=k;j++){
        v2[i]+=v1[j];
    }
cout<<v2[i]<<endl;
}

Shifting and Copying std::vector elements


By : Capreolus
Date : March 29 2020, 07:55 AM
it fixes the issue Looks like you forgot the template argument for std::vector. Anyway, try something like:
code :
std::vector<int> array2(n+1);
std::vector<int> array1(array2.begin()+1, array2.end());

Copying the elements of one vector into another


By : no name
Date : March 29 2020, 07:55 AM
Any of those help I need to copy the elements of one vector into another, but in the same process I need to be able to remove the comments or garbage from the data. For example; two of the elements are , Say
code :
string str = "(* Month: 2005 01 *) 31";
size_t p = str.find_last_of(" ");
string sub_str = str.substr(p+1)

Copying vector elements to a vector pair


By : MDMC
Date : March 29 2020, 07:55 AM
To fix the issue you can do You have clarified that the arrays will always be of equal size. That's a prerequisite condition.
So, your situation is as follows. You have vector A over here, and vector B over there. You have no guarantees whether the actual memory that vector A uses and the actual memory that vector B uses are next to each other. They could be anywhere.
code :
pairVector.reserve(pairVector.size()+strVector.size());
for (int i = 0; i < strVector.size(); ++i )
    pairVector.push_back(pair<string, int> (strVector[i], intVector[i]));
    pairVector.emplace_back(strVector[i], intVector[i]);
int i=strVector.size();
for (int i = 0; i < n; ++i )

Copying elements of rapidjson::Value to std::vector


By : Achilleas Mantzios
Date : March 29 2020, 07:55 AM
hop of those help? The std::vector vector must be assignable, so you cannot have a std::vector of const references. Instead, try storing either rapidjson::Values or pointers to them. If you really want to store references, check out std::reference_wrapper.
From section 23.2.4 Class template vector of the C++ standard:
Related Posts Related Posts :
  • store strings in stable memory in c++
  • Why is static_cast used in QT's official document
  • iterator .end() from std::list returns "0xcdcdcdcdcdcdcdcd" but .begin() as expected
  • Is std::sqrt the same as sqrt in C++
  • Iterate through std::initializer_list
  • Codeblocks c++ code doesn't run in VS 19 (vector subscript out of range)
  • Why erase on std::vector promote iterator
  • how to destroy an object in C++
  • How to create Visual Studio 2015 solution from CMake
  • Using concepts for checking if a type T has a field F
  • constructor giving error: no matching function for call to
  • search top n% of a vector member C++
  • Is this reinterpret_cast problematic in principle, and/or in practice?
  • What is the following error doing? I do not see any error with the bounds
  • Two index's of an array have same memory adress
  • how do i avoid integer division in c++?
  • Setting value to enum
  • Properties of a pointer to a zero length array
  • Why the output is different how ever the formula is the same?
  • Restarting from the beginning using do while loops
  • Error: invalid initialization of reference of type
  • how to avoid to use memcpy to create a string
  • Is there any class pointers in Perl in order to access member variables and functions?
  • Why the static variable is not set to 1000
  • Why can't a destructor have reference qualifiers?
  • How to print binary tree in horizontal way?
  • Comparison behavior of ' <' operator
  • Constructors in C++ Language
  • Why displayed value of b , c and y is different from my trace?
  • Undefined reference to `fftw_init_threads' while installing pHash library
  • Reading remapped hdd sectors
  • why the result is 1?
  • YouCompleteMe conf file for inspecting libraries header files without reporting the library errors
  • How CMake finds packages
  • Get UTC epoch time till start of current year in C++
  • access to iterator in lambda function of an algorithm cause me segmentation fault
  • How to prevent bool to int conversion in constructor?
  • std::map with keys that have no ordering
  • Different uses of noexcept
  • Invoking `constexpr` member function through reference - clang vs gcc
  • Why do I need to provide constructor implementation in header? C++
  • unsigned long cannot hold the correct number over 2,147,483,647
  • Take as input str, a string. Write a code which moves all ‘x’ from the string to its end.Print the value returned
  • How to compile C ++ code from Windows for Linux (Dev-Cpp)
  • rand with vector of strings in a multimap
  • How to get object type of pointer to non-static data member at compile time?
  • difference between *b= *b+1 and *b++
  • Can a core constant expression contain an ignored reinterpret_cast?
  • Adjusting CMake compiler commands to account for weirdness
  • How can I input a state to a variable of enum type in C++?
  • Reading from stream to initialize a read-only variable
  • Empty std::array<T, 0> doesn't have constexpr begin()?
  • Why references have types even though they are not objects?
  • Reverse of an array Hackerrank
  • How can I show that assignment is not atomic?
  • Allocate more RAM to executable
  • VS2019 fatal error C1083: Cannot open compiler intermediate file: xxxx.ipdb: Not enough space
  • RAII and members if constructor throws?
  • C++ The correct way to multiply an integer and a double
  • how to convert const Uint8* to Uint8*
  • shadow
    Privacy Policy - Terms - Contact Us © voile276.org