#include <stdio.h>
void swaprows(int arr[4][4], int row1, int row2);
int main ()
{
    int arr[4][4]={ {1,2,3,4}, {5,6,7,8}, {9,10,11,12}, {13,14,15,16} };
    int row1;
    int row2;
    int i, j;

    printf("This is the 2D array...\n");
    for(i=0; i<4; i++)
     {
       for(j=0; j<4; j++)
        printf("%2d ", arr[i][j]);
       printf("\n");
     }

    printf("\nWhich rows would you like to swap?");
    scanf("&d" "&d", row1, row2);

    swaprows(arr,row1,row2);

    system("PAUSE");
    return 0;
}

void swaprows(int arr[4][4], int row1, int row2)
{
   int i, j;

   if (row1==row2)
    {
      printf("After swapping...\n");
      for(i=0; i<4; i++)
       {
        for(j=0; j<4; j++)
         printf("%2d ", arr[i][j]);
        printf("\n");
       }
    }

   else if ((row1>=0 && row1<=3) && (row2>=0 && row2<=3))
    {
      int temp[4][4]={0};
      for (i=0; i<4; i++)
       {
         temp[row1][i]=arr[row1][i];
         arr[row1][i]=arr[row2][i];
         arr[row2][i]=arr[row1][i];
       }
    printf("After swapping...\n");
      for(i=0; i<4; i++)
       {
        for(j=0; j<4; j++)
         printf("%2d ", arr[i][j]);
        printf("\n");
       }
    }

   else
      printf("Error: invalid entry.\n\n");

  return 0;
}