how to create vector of vector in c++ code example

Example 1: initialize vector of vector c++

#include <iostream>
#include <vector>
 
#define M 3
#define N 4
 
int main()
{
  // specify default value to fill the vector elements
  int default_value = 1;
  // first initialize a vector of ints with given default value
  std::vector<int> v(N, default_value);
  // Use above vector to initialize the two-dimensional vector
  std::vector<std::vector<int>> matrix(M, v);
  
  return 0;
}

Example 2: how to create a vector in c++

// CPP program to create an empty vector 
// and push values one by one. 
#include <vector>

using namespace std;
int main() 
{ 
    // Create an empty vector 
    vector<int> vect;  
    //add/push an integer to the end of the vector
    vect.push_back(10); 
	//to traverse and print the vector from start to finish
    for (int x : vect) 
        cout << x << " ";

    return 0; 
}

Example 3: how to make a vector in c++

#include <vector>

using namespace std;

int main(){
  vector<int> v;
  //vector<type> name
  
  return 0;
}

Example 4: create vectors of vectors c++

typedef std::vector<std::vector<double> > Matrix;

Matrix matrix = { {0.1,1.1,.2},
                 {.4,.5,.6}, 
                 {.8,.9,.10}
                };
// Just initilization:
int rows = 3;
int cols = 3;
Matrix m3(rows, std::vector<double>(cols) );