Thread: Array pointers question?

Well, not every int would become a double. For example, the variables holding the number of elements would still remain ints. What code did you end up with?

There are other things wrong with the code. malloc() shouldn't be casted; stdlib.h should be included (for exit() and malloc() and free()); math.h doesn't need to be included; main should not use the implicit int rule and should return int. There are also things I would change but are not strictly wrong: declaring variables in the middle of a block is C99, and Total starts capitalized whereas the other variables do not.

This doesn't work? I've made all of my changes blue (except for the malloc casts, which I just removed).

Code:

#include<stdio.h>
#include <stdlib.h>  /* added this and removed the malloc() casts */
#include<math.h>
main(){    

              int a,b,c;
int i,j,k,p;
double *aptr;
int nrows, ncols; 
printf("How many rows would you like store?\n ");
  scanf("&#37;d", &nrows);
  printf("How many columns would you like to store?\n ");
  scanf("%d", &ncols);
  printf("Enter the number of nearest neighbours p: ");
  scanf("%d", &p);
int row, col;
int Total=nrows*ncols;
double **rptr = malloc(nrows * sizeof(double *));
if (rptr == NULL)
{
puts("\nFailure to allocate room for pointers");
exit(0);
}   

/* we now allocate the memory for the array */
 aptr = malloc(Total* sizeof(double));
if (aptr == NULL)
{
puts("\nFailure to allocate room for the array");
exit(0);
}
/* and now we 'point' the pointers */
for (k = 0; k < nrows; k++)
{
rptr[k] = aptr + (k * ncols);
}
 for(i=0 ; i<Total; ++i) 
    {
    printf("Enter data row wise: ");
    scanf("%lf", &aptr[i]);
    }
printf("\n\nAnd now we print out the array\n");
for (row = 0; row < nrows; row++)
{
for (col = 0; col < ncols; col++)
{
printf("%f \t", rptr[row][col]);}
printf("\n\n");
getchar();

       }   free(rptr);
       free(aptr);  }

BTW, your indentation could use some working on.