initialise and declare a vector 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: initialize vector c++

// CPP program to create an empty vector
// and push values one by one.
#include <bits/stdc++.h>
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;
}