#include <iostream.h>
#include <string.h>
#if !defined(__WIN32__)
extern "C" {
#endif
#include <stdlib.h>
#if !defined(__WIN32__)
}
#endif

int*** matrix3d(int h, int w, int d, int x=0) {
   // this function allocates an
   // h x w x d three dimensional matrix
   // and initializes the slots with x

   int*** a = new int**[h]; 
   for(int i=0; i<h; i++) {
      a[i] = new int*[w];
      for(int j=0; j<w; j++) {
         a[i][j] = new int[d];
         for(int k=0; k<d; k++) {
            a[i][j][k] = x;
         }
      }
   }
  
   return a;
}

void release3d(int*** m, int h, int w) {
   // release memory associate with 
   // m, which is a 3d array m[h][w][]

   for(int i=0; i<h; i++) {
      for(int j=0; j<w; j++) {
         delete [] m[i][j];
      }
      delete [] m[i];
   }

   delete [] m;
}

int ** matrix2d(int w, int h, int x = 0) {
   // this function allocates a two dimensional
   // array C style (not C++), and initializes the
   // elements to x
   int ** a = (int**)malloc(w*sizeof(int*));
   for(int i=0; i<w; i++) {
      a[i] = (int*)malloc(h*sizeof(int));
      for(int j=0; j<h; j++) {
         a[i][j] = x;
      }
   }
   return a;
}

void release2d(int ** m, int w) {
   // release the 2d array m[w][] C style
   for(int i=0; i<w; i++) {
      free(m[i]);
   }
   free(m);
}

int main() {

   char* name = "Santa Claus";

   cout << name << endl;
   
   char buffer[256];
   cout << "eneter your name> ";
   cout.flush();
   cin >> buffer;
  
   int n = strlen(buffer); 
   char* nb = new char[n+1]; // why do I need + 1??
   for(int i=0; i<n; i++) {
      nb[i] = buffer[n-i-1];
   }
   nb[n] = '\0';

   cout << "your name \"" << buffer << "\" backwards: \"" 
        << nb << "\"" << endl;
   
   delete [] nb;

   // REMEMBER, C's new, new[], delete and delete[]
   // should not be used together with C's malloc, calloc,
   // realloc and free, unless you really know what you
   // are doing. (see the note on page 37)

   int *** m = matrix3d(2,3,2,7);

   cout << "m[0][1][1] = " << m[0][1][1] << endl;
 
   release3d(m,2,3);

   int ** k = matrix2d(3,2,-2);

   cout << "k[2][0] = " << k[2][0] << endl;

   release2d(k,3);

   return 0;
}