Question

HOW TO PRINT THE CONTENTS OF A TWO-DIMENSIONAL ARRAY USING POINTER ARITHMETIC (USING FUNCTIONS)

(C++)

Fill out the function definition for "void print_2darray_pointer(double *twoDD, int row, int col)".

Should match the output from the function void print_2darray_subscript(double twoDD[][ARRAY_SIZE], int row, int col)

# include
using namespace std;

   const int ARRAY_SIZE = 5;
   const int DYNAMIC_SIZE = 15;
   const int TIC_TAC_TOE_SIZE = 3;

   // function definitions:

   void print_2darray_subscript(double twoDD[][ARRAY_SIZE], int row, int col)
       // printing array using subscripts
   {
       for (int i = 0; i < row; i++)
       {
           for (int j = 0; j < col; j++)
           {
               cout << twoDD[i][j] << " ";
           }
           cout << endl;
       }
       cout << endl;
   }

   void print_2darray_pointer(double *twoDD, int row, int col)
       // print array using pointer arithmetic
   {

       for (int i = 0; i < row; i++)
       {
           for (int j = 0; j < col; j++)
           {

              
               // I tried doing this, but it didn't work : cout << *(*(twoDD + i) + j);

               // our 2d array is layed out linearly in memory as contiguous rows, one after another, there are #row rows
               // each row has #col columns

               // to compute the offset using pointer math
               // offset from twoDD: #row (i) * #col + #col (j), result: pointer to array element
               // ...
           }
           cout << endl;
       }
       cout << endl;
   }

   //------------------------------------------------------------------------------

int main()
{

   // complete the following function implementations
   // Q#3 - pointer arithmetic, indexing multidimensional arrays

   double twoDDoubles[ARRAY_SIZE][ARRAY_SIZE] = { {1,2,3,4,5},{6,7,8,9,10},{11,12,13,14,15},{16,17,18,19,20},{21,22,23,24,25} };

   cout << endl << "print 2d array of doubles" << endl << endl;

   // print 2ddoubles via subscript operator
   print_2darray_subscript(twoDDoubles, ARRAY_SIZE, ARRAY_SIZE);

   // print 2ddoubles via pointer arithmetic
   print_2darray_pointer((double*)twoDDoubles, ARRAY_SIZE, ARRAY_SIZE);

   cout << endl << endl;
   system("pause");
   return 0;
}

Answer 1

//Use this code

#include<iostream>

using namespace std;

const int ARRAY_SIZE = 5;
const int DYNAMIC_SIZE = 15;
const int TIC_TAC_TOE_SIZE = 3;

// function definitions:

void print_2darray_subscript(double twoDD[][ARRAY_SIZE], int row, int col)
// printing array using subscripts
{
   for (int i = 0; i < row; i++)
   {
       for (int j = 0; j < col; j++)
       {
           cout << twoDD[i][j] << " ";
       }
       cout << endl;
   }
   cout << endl;
}

void print_2darray_pointer(double* twoDD, int row, int col)
// print array using pointer arithmetic
{

   for (int i = 0; i < row; i++)
   {
       for (int j = 0; j < col; j++)
       {
           cout << *((twoDD + i*col)+j) << " ";
          
       }
       cout << endl;
   }
   cout << endl;
}

//------------------------------------------------------------------------------

int main()
{

   // complete the following function implementations
   // Q#3 - pointer arithmetic, indexing multidimensional arrays

   double twoDDoubles[ARRAY_SIZE][ARRAY_SIZE] = { {1,2,3,4,5},{6,7,8,9,10},{11,12,13,14,15},{16,17,18,19,20},{21,22,23,24,25} };

   cout << endl << "print 2d array of doubles" << endl << endl;

   // print 2ddoubles via subscript operator
   print_2darray_subscript(twoDDoubles, ARRAY_SIZE, ARRAY_SIZE);

   // print 2ddoubles via pointer arithmetic
   print_2darray_pointer((double*)twoDDoubles, ARRAY_SIZE, ARRAY_SIZE);

   cout << endl << endl;
   system("pause");
   return 0;
}

//Output

//If you need any help regarding this solution ......... please leave a comment ...... thanks