这样释放内存对吗？ [复制链接]

分配：
void ***alloc3 (size_t n1, size_t n2, size_t n3, size_t size)
{
   size_t i3,i2;
   void   ***p;
   if ((p=(void***)malloc(n3*sizeof(void**)))==NULL)  return NULL;
   if ((p[0]=(void**)malloc(n3*n2*sizeof(void*)))==NULL) {
      free(p);
      return NULL;
      }
   if ((p[0][0]=(void*)malloc(n3*n2*n1*size))==NULL) {
      free(p[0]);
      free(p);
      return NULL;
      }
   for (i3=0; i3<n3; i3++) {
      p[i3] = p[0] + n2*i3;
      for (i2=0; i2<n2; i2++)
         p[i3][i2] = (char*)p[0][0]+size*n1*(i2+n2*i3);
      }
   return p;
}

释放：
void free3 (void ***p)
{
   free(p[0][0]);
   free(p[0]);
   free(p);
}

I think  you are making a 3D array.  Do the following:


template< class T>
void create3DArray( const unsigned nx, const unsigned ny, const unsigned nz, T *** & array )
{
     if ( array != NULL )
     {
          return;
     }

     unsigned i( 0 ), j( 0 );
     array = new T **[ nx ];
     for ( i = 0; i < nx; ++i )
     {
        array[ i ] = new  T*[ ny ];
     }
  
     for ( i = 0; i < nx; ++i )
     {
           for ( j = 0; j < ny; ++j )
           {
               array[ i ][ j ] = new T[ nz ];
           }
     }
}

template< class T>
void delete3DArray( const unsigned nx, const unsigned ny, T *** & array )
{
     if ( array == NULL )
     {
          return;
     }
  
     unsigned i( 0 ), j( 0 );
     for ( i = 0; i < nx; ++i )
     {
           for ( j = 0; j < ny; ++j )
           {
               delete[] array[ i ][ j ];
           }
     }

     for ( i = 0; i < nx; ++i )
     {
        delete[] array[ i ];
     }

     delete[] array; array = NULL;
}

Note that do not forget []  for delete. Otherwise, there is memory leak. You need to know why.

[quote]引用楼主xlttap于2010-04-07 10:28发表的 这样释放内存对吗？

分配：
void ***alloc3 (size_t n1, size_t n2, size_t n3, size_t size)
{
   size_t i3,i2;
   void   ***p;
   if ((p=(void***)malloc(n3*sizeof(void**)))==NULL)  return NULL;
   if ((p[0]=(void**)malloc(n3*n2*sizeof(void*)))==NULL) {
      free(p);
      return NULL;
      }
   if ((p[0][0]=(void*)malloc(n3*n2*n1*size))==NULL) {
      free(p[0]);
      free(p);
      return NULL;
      }
   for (i3=0; i3<n3; i3++) {
      p[i3] = p[0] + n2*i3;
      for (i2=0; i2<n2; i2++)
         p[i3][i2] = (char*)p[0][0]+size*n1*(i2+n2*i3);
      }
   return p;
}

释放：
void free3 (void ***p)
{
   free(p[0][0]);
   free(p[0]);
   free(p);
}
这个代码是我们老板（几十年开发经验）写的，我没看懂他为什么这样释放，所以了上来问问。

Check my code again. I made a little change. One place was not displayed properly.

Experience helps and is not everything you can count on.
The best coders are the guys who make fewer mistakes and are able to find and fix bugs quickly.

do you know the difference between

and
  
?