2D Array in Cpp (c++)

2D-Array:

2D array is similar to a matrix of mxn (row into column). where every element has a specific index which is usually denoted by i and j. i represent the number of rows and j represent the number of columns.

 

Declaration of 2D Array in C++

int A[5][4];                                               // 5 rows and 4 column

Initialization Of Array:

An array initializer for a 2D array contains the rows of A, separated by commas and enclosed in braces. Each row, in turn, is a list of values separated by commas and enclosed in braces.

int A[5][4] = { 
                     {  1,  2, 3, 4 },
                     { -44, 65, 4, 23},
                     { -45, -1, 3, 34}
                     { -45, -1, 3, 34}
                     { -45, -1, 3, 34}
                  };

There are three-dimensional, four-dimensional, and even higher-dimensional arrays, but they are not used very often in used.

2D array as a pointer:

int **ptr = new int * [row];
 for(x=0;x<row;x++)
 *(ptr+x) = new int [col];

Implementation of 2D Array in C++:

#include<iostream>

using namespace std;

int main()
{

     int row,col,x,y;

    cout<<"Enter number of rows: ";
 cin>>row;

    cout<<"Enter number of columns: ";
 cin>>col;

     int **ptr = new int * [row];


      for(x=0;x<row;x++)

      *(ptr+x) = new int [col]; //Storing elements

       for (x=0;x<row;x++)
       for(y=0;y<col;y++)
       {
             cout<<"Enter number: ";
             cin>>ptr[x][y];
        }

        //Displaying pointer to pointer to ptr

        cout<<"You have entered:"<<endl;

 for (x=0;x<row;x++)
 {
  for(y=0;y<col;y++)
  {
   cout<<ptr[x][y]<<" ";
  }
  cout<<endl;
 }

 return 0;
}