CPP

2d vector initialization in cpp

vector<vector<int>> vec( n , vector<int> (m, 0));

where: n is number of ROWS,
	   m is number of COLUMNS
       
So result will be ( Let n = 2, m = 3 )
  	[[ 0, 0, 0],
     [ 0, 0, 0]]
     		   ( 2 x 3 )

how to make a 2d vector in c++

// Create a vector containing n 
//vectors of size m, all u=initialized with 0
vector<vector<int> > vec( n , vector<int> (m, 0));  

how to initialize 2d vector in c++

#include <iostream>
#include <vector>
#include <algorithm>
 
int main()
{
    std::vector<int> v = {2, 1, 3, 6, 7, 9, 8};
 
    int max = *max_element(v.begin(), v.end());
    int min = *min_element(v.begin(), v.end());
 
    std::cout << min << ", " << max << std::endl;        // 1, 9
 
    return 0;
}

2d array using vector

// CPP program
#include <iostream>
#include <vector>
using namespace std;
int main()
{
    int n = 4;
    int m = 5;
 
    /*
    Create a vector containing "n"
    vectors each of size "m".
    */
    vector<vector<int>> vec( n , vector<int> (m));
 
    for(int i = 0; i < n; i++)
    {
        for(int j = 0; j < m; j++)
        {
            vec[i][j] = j + i + 1;
        }
    }
 
    for(int i = 0; i < n; i++)
    {
        for(int j = 0; j < m; j++)
        {
            cout << vec[i][j] << " ";
        }
        cout << endl;
    }
     
   return 0;
}

2d vector c++ declaration

vector< vector<int>> a(rows, vector<int> (cols));

2d vector cpp

For user defined size:

vector<vector<int>> vec( n ); 
where n -> number of rows

vector<vector<int>> vec( n , vector<int> (m, 0)); 
where n -> number of rows
where m -> number of columns (all initialized with 0)
  

how to initialize 2d vector in c++

#include<vector>
#include<algorithm>

// all the  std and main syntax ofcourse.

vector<int> pack = {1,2,3} ;

// To add at the END
pack.push_back(6);       // {1,2,3,6}

//  OR
// To add at BEGGINING 
pack.insert(pack.begin(),6) 	// {6,1,2,3,}		

create a 2d vector in c++

// CPP program
#include <iostream>
#include <vector>
using namespace std;
int main()
{
    int n = 3;
    int m = 4;
 
    /*
    We create a 2D vector containing "n"
    elements each having the value "vector<int> (m, 0)".
    "vector<int> (m, 0)" means a vector having "m"
    elements each of value "0".
    Here these elements are vectors.
    */
    vector<vector<int>> vec( n , vector<int> (m, 0));
 
    for(int i = 0; i < n; i++)
    {
        for(int j = 0; j < m; j++)
        {
            cout << vec[i][j] << " ";
        }
        cout<< endl;
    }
     
    return 0;
}

how to initialize 2d vector in c++

#include<vector>
#include<algorithm>      //**********Have to include THIS...OTHERWISE

sort( vectorName.begin(),vectorName.end() ) ;

2D vector in cpp

// CPP program
#include <iostream>
#include <vector>
using namespace std;
int main()
{
    int n = 3;
    int m = 4;
  
    /*
    We create a 2D vector containing "n"
    elements each having the value "vector<int> (m, 0)".
    "vector<int> (m, 0)" means a vector having "m"
    elements each of value "0".
    Here these elements are vectors.
    */
    vector<vector<int>> vec( n , vector<int> (m, 0)); 
  
    for(int i = 0; i < n; i++)
    {
        for(int j = 0; j < m; j++)
        {
            cout << vec[i][j] << " ";
        }
        cout<< endl;
    }
      
    return 0;
}

2D vector in cpp

// CPP program
#include <iostream>
#include <vector>
using namespace std;
int main()
{
    int n = 3;
    int m = 4;
  
    /*
    We create a 2D vector containing "n"
    elements each having the value "vector<int> (m, 0)".
    "vector<int> (m, 0)" means a vector having "m"
    elements each of value "0".
    Here these elements are vectors.
    */
    vector<vector<int>> vec( n , vector<int> (m, 0)); 
  
    for(int i = 0; i < n; i++)
    {
        for(int j = 0; j < m; j++)
        {
            cout << vec[i][j] << " ";
        }
        cout<< endl;
    }
      
    return 0;
}

how to create 2d array using vector in c++

vector<vector<int>> vec(N, vector<int> (M, INT_MAX));

Explanation::
vector<vector<int>> -- will take the formed container
N -- Think like row of 2d Matrix
vector<int> (M, INT_MAX) -- In each row, there is again a vector associated with it, 
that will formed 2d array.