CPP

c++ initialize vector of vector with size

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

define vector with size and value c++

// CPP program to create an empty vector
// and push values one by one.
#include <iostream>
#include <vector>
using namespace std;
 
int main()
{
    int n = 3;
 
    // Create a vector of size n with
    // all values as 10.
    vector<int> vect(n, 10);
 
    for (int x : vect)
        cout << x << " ";
 
    return 0;
}

set size of a vector c++

void resize (size_type n, value_type val = value_type());

c++ initialize size of 3d vector

vector<vector<vector<double>>> f(3, vector<vector<double>>(4, vector<double>(5)));

set size of a vector c++

void resize (size_type n);
void resize (size_type n, const value_type& val);

vector with initial size

std::vector<std::string> vec(20000);

c++ create vector of size

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

for(int x = 0; x < 20; ++x)
   arr[x] = x;