Why is D significantly slower than C# in this instance?

[Artjom]

On Monday, 10 April 2023 at 21:18:59 UTC, Artjom wrote:
> I have written this simple bruteforce algorithm that finds max 
> sum of subsequence in some sequence, both in C# and D. And when 
> the size of array is 1000000 elements - D is 20 seconds lated. 
> Why?
> D code (algorithm):
> '
>     public int solveBruteForce()
>     {
>         int currMax = arr[0], currSum;
>         foreach (_; arr)
>         {
>             currSum = 0;
>             foreach (int el; arr)
>             {
>                 currSum += el;
>                 currMax = max(currSum, currMax);
>             }
>         }
>
>         return currMax;
>     }
> '
> D code (measuring exec time):
> '
>     double measureTime()
>     {
>         StopWatch sw;
>         sw.start();
>         solveDynamic();
>         double sec = (to!double(sw.peek.total!"msecs") / 1000) 
> + (to!double(sw.peek.total!"usecs") / 1000000);
>         return sec;
>     }
> '
> C# code (alg):
> '
> int EachOther(int[] array)
> {
>     int current_max = array[0];
>     for (int i = 0; i < array.Length; i++)
>     {
>         int subset_sum = 0;
>         for (int j = i; j < array.Length; j++)
>         {
>             subset_sum += array[j];
>             current_max = Math.Max(subset_sum, current_max);
>         }
>     }
>     return current_max;
> }
> '
> C# code (time measuring):
> '
>     Stopwatch stopwatch = new Stopwatch();
>     for (int cur_size = 1000; cur_size <= size_max; cur_size *= 
> 10)
>     {
>         int[] array = GenArray(cur_size);
>         stopwatch.Start();
>         EachOther(array);
>         stopwatch.Stop();
>         double time = (double)stopwatch.ElapsedTicks / 
> Stopwatch.Frequency;
>         Console.Write("{0, -10}|", string.Format("{0:f7}", 
> time));
>     }
>     Console.WriteLine();
> '

Sorry, wrong code formatting
> D code (algorithm):
```
     public int solveBruteForce()
     {
         int currMax = arr[0], currSum;
         foreach (_; arr)
         {
             currSum = 0;
             foreach (int el; arr)
             {
                 currSum += el;
                 currMax = max(currSum, currMax);
             }
         }

         return currMax;
     }
```
> D code (measuring exec time):
```
double measureTime()
{
  StopWatch sw;
  sw.start();
  solveDynamic();
  double sec = (to!double(sw.peek.total!"msecs") / 1000) + 
(to!double(sw.peek.total!"usecs") / 1000000);
  return sec;
}
```
> C# code (alg):
```
int EachOther(int[] array)
{
  int current_max = array[0];
  for (int i = 0; i < array.Length; i++)
  {
     int subset_sum = 0;
     for (int j = i; j < array.Length; j++)
     {
         subset_sum += array[j];
         current_max = Math.Max(subset_sum, current_max);
      }
   }
  return current_max;
}
```
> C# code (time measuring):
```
Stopwatch stopwatch = new Stopwatch();
for (int cur_size = 1000; cur_size <= size_max; cur_size *= 10)
{
int[] array = GenArray(cur_size);
stopwatch.Start();
EachOther(array);
stopwatch.Stop();
double time = (double)stopwatch.ElapsedTicks /
Stopwatch.Frequency;
Console.Write("{0, -10}|", string.Format("{0:f7}", time));
}
Console.WriteLine();
```