Foreach loop behaviour and manipulation

[Joseph Rushton Wakeling]

On 29/11/13 00:36, Binarydepth wrote:
> I'm wondering in the case of manipulating the variable from the foreach loop, Do
> I have to reset that variable so the loop can work as intended ?(chronologically).

I think that you are approaching this problem in the wrong way.  Instead of 
using a temporary variable to preserve the loop value, why not keep the loop 
value constant (immutable, in fact) and use a temporary variable to calculate 
the values that you wish to write to the array?

Like so:

////////////////////////////////////////////////////////////////////////
import std.stdio : write, readf;
void main()
{
     int a, r, f;
     int[102] arr;
     write("Digite su año de nacimiento : ");
     readf(" %d", &a);
     write("\n");
     foreach (immutable t; 1 .. 51)
     {
         int temp = (((t * 20) + 420) * 5) + 3;
         arr[t - 1] = temp - a;
         temp = (((t * 5) + 50) * 20) + 1013;
         arr[t] = temp - a;
     }
     write("BD\tAnonimo\n");
     foreach(count; 0..102)
     {
         write(arr[count]);
         if(count%2==0)
             write("\n");
         else
             write(" : ");
     }
}
////////////////////////////////////////////////////////////////////////

This gives same results as your existing code but (to me at least) is much 
simpler and easier to follow.

2nd thing -- do I assume right that you are getting incorrect output and that 
the later output values shouldn't be all zero?  I think this is because you are 
incorrectly choosing array indexes to write to, but we should perhaps talk about 
what your program is _supposed_ to do before addressing that.

Am I also right to assume that you're used to languages where the array index 
starts from 1 rather than from 0?

Best wishes,

     -- Joe