c 2b 2b define vector with size

1vector<vector<int>> v(10, vector<int>(10));

1#include <vector>
2
3int main() {
4  std::vector<int> myVector = { 666, 1337, 420 };
5  
6  size_t size = myVector.size(); // 3
7  
8  myVector.push_back(399); // Add 399 to the end of the vector
9  
10  size = myVector.size(); // 4
11}

1#include <iostream>
2#include <vector>
3
4using namespace std;
5
6int main(void) {
7   vector<int> v;
8
9   cout << "Initial vector size = " << v.size() << endl;
10
11   v.resize(5, 10);
12   cout << "Vector size after resize = " << v.size() << endl;
13
14   cout << "Vector contains following elements" << endl;
15   for (int i = 0; i < v.size(); ++i)
16      cout << v[i] << endl;
17
18   return 0;
19}

1// create a vector with 20 integer elements
2std::vector<int> arr(20);
3
4for(int x = 0; x < 20; ++x)
5   arr[x] = x;

1#include <vector>
2
3auto n = 20
4// create a vector with n=20 integer elements
5std::vector<int> arr(n);

1vector<Entry> array(1000);//size of 1000
2