how to initialize a vector in c 2b 2b

1// CPP program to create an empty vector 
2// and push values one by one. 
3#include <vector>
4
5using namespace std;
6int main() 
7{ 
8    // Create an empty vector 
9    vector<int> vect;  
10    //add/push an integer to the end of the vector
11    vect.push_back(10); 
12	//to traverse and print the vector from start to finish
13    for (int x : vect) 
14        cout << x << " ";
15
16    return 0; 
17}

1// First include the vector library:
2#include <vector>
3
4// The syntax to create a vector looks like this:
5std::vector<type> name;
6
7// We can create & initialize "lol" vector with specific values:
8std::vector<double> lol = {66.666, -420.69};
9
10// it would look like this: 66.666 | -420.69

1 vector<int> arr(10,0);

1#include <iostream>
2#include <vector>
3 
4#define M 3
5#define N 4
6 
7int main()
8{
9  // specify default value to fill the vector elements
10  int default_value = 1;
11  // first initialize a vector of ints with given default value
12  std::vector<int> v(N, default_value);
13  // Use above vector to initialize the two-dimensional vector
14  std::vector<std::vector<int>> matrix(M, v);
15  
16  return 0;
17}
18

1#include <bits/stdc++.h> 
2#include <vector> 
3using namespace std; 
4  
5int main() 
6{ 
7// This vector initializes with the values: 10, 20, and 30
8  vector<int> vect{ 10, 20, 30 }; 
9
10    return 0; 
11} 

1std::vector<type> name;