vector 2D code example

Example 1: 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));

Example 2: 2d vector

#include <bits/stdc++.h>
using namespace std;
int main() 
{
  int rows = 2;
  int cols = 2;
  int val = 1;
  vector< vector<int> > v(rows, vector<int> (cols, val));  /*creates 2d vector “v[rows][cols]” and initializes all elements to “val == 1” (default value is 0)*/
  v[0][0] = 5;
  v[1][1] = 4;
  cout << v[0][0] << endl; //Output: 5cout << v[1][0] << endl; //Output: 1return 0;}

Example 3: 2d vector

#include <bits/stdc++.h>
using namespace std;
main() {
	int r=2,c=3,val=1;
	vector<vector<int>> v(r,vector<int>(c,val)); 
	/*
    2d vector “v[r][c]”;
    all elements = val; 
    (default value is 0)
    */
	for(int i=0;i<r;i++) 
		for(int j=0;j<c;j++) 
  			cout<<v[i][j]<<" ";
        cout<<endl;
  	/*
    1 1 1
    1 1 1
    */
}

Example 4: how to take input in 2d vector in c++

std::vector<vector<int>> d;
//std::vector<int> d;
cout<<"Enter the N number of ship and port:"<<endl;
cin>>in;
cout<<"\Enter preference etc..:\n";
for(i=0; i<in; i++){ 
cout<<"ship"<<i+1<<":"<<' ';
    for(j=0; j<in; j++){
    cin>>temp;
    d.push_back(temp);// I don't know how to push_back here!!
    }
}

Example 5: 2d vector

vector<vector<int>> v(row,vector<int>(col,val));