Can you make sense of this C pointer code?

I have this snippet of C code that uses pointers in a very confusing way.

   // We first point to a specific location within an array..
   double* h = &H[9*i];
   int line1 = 2*n*i;
   int line2 = line1+6;

   // ..and then access elements using that pointer, somehow..
   V[line1+1]=h[0]*h[4] + h[3]*h[1];

What's happening here? how do I write something equivalent in C#?


You don't really write something equivalent in C# because you don't have pointers there (except by invoking unsafe code) - to get an element from a C# array, you need an array ref and an index, and you index into the array.

You can, of course, do the same with a C array. We convert the C pointer-arithmetic into C array-indexing:

int h_index = 9 * i;
int line1 = 2 * n * i;
int line2 = line1 + 6;

V[line1 + 0] = H[h_index] * H[h_index + 1];
V[line1 + 1] = H[h_index] * H[h_index + 4] + H[h_index + 3] * H[h_index + 1];

And then we have something that can be used pretty much verbatim in C#.

Need Your Help

Why doesn't toolstriplabel's backcolor property change during design time or run time?

.net properties delphi-prism toolstrip backcolor

I need to have a toolstrip label and its back color changed during runtime, but no matter what I do. It just won't change its backcolor, even though they give option to change its backcolor. Why is...

“Could not find the specified key ”ProductsLandingPageTitle“ or class id ”ProductsResources“” in Sitefinity

.net sitefinity-4

I add sample product module to my project, set it as show in documentation, and after restart application get error.