how to make a dynamic 2d array in c++ code example

Example 1: Create dynamic 2d array in java

// Create dynamic 2d array in java
import java.util.ArrayList;
import java.util.List;
public class Dynamic2dArray 
{
   public static void main(String[] args) 
   {
      List<int[]> li = new ArrayList<>();
      li.add(new int[]{2,4,6});
      li.add(new int[]{3,5});
      li.add(new int[]{1});
      // element at row 0, column 0
      System.out.println("Element at [0][0]: " + li.get(0)[1]);
      // get element at row : 1, column : 1
      System.out.println("Element at [1][1]: " + li.get(1)[1]);
   }
}

Example 2: declaring 2d dynamic array c++

int** arr = new int*[10]; // Number of Students
int i=0, j;
for (i; i<10; i++) 
	arr[i] = new int[5]; // Number of Courses
/*In line[1], you're creating an array which can store the addresses
  of 10 arrays. In line[4], you're allocating memories for the 
  array addresses you've stored in the array 'arr'. So it comes out 
  to be a 10 x 5 array. */

Example 3: array 2d dynamic allocation c++

int** a = new int*[rowCount];
for(int i = 0; i < rowCount; ++i)
    a[i] = new int[colCount];