Answers for "set size vector c++"

c++ initialize vector of vector with size

vector<vector<int>> v(10, vector<int>(10));

c++ vector size

#include <vector>

int main() {
  std::vector<int> myVector = { 666, 1337, 420 };
  
  size_t size = myVector.size(); // 3
  
  myVector.push_back(399); // Add 399 to the end of the vector
  
  size = myVector.size(); // 4
}

c++ vector extend vector

std::vector<int> a = {1, 2};
std::vector<int> b = {3, 4, 5};
a.insert(a.end(), b.begin(), b.end()); // a = {1, 2, 3, 4, 5}

c++ vector resize

std::vector<int> vec = {1, 2, 3};
vec.resize(2); // {1, 2}
vec.resize(4); // {1, 2, 0, 0,}
vec.resize(6, 9);  // {1, 2, 0, 0, 9, 9}

declare vector of size n in c++

#include <vector>

auto n = 20
// create a vector with n=20 integer elements
std::vector<int> arr(n);