In C# i solve simple way with cast

     int positiveCount = 0;
     int negativeCount = 0;
     int zeroCount = 0;

     foreach(int num in arr){
        if (num > 0)
            positiveCount++;
        else if (num < 0)
            negativeCount++;
        else 
            zeroCount++;
     }

     double positiveRatio = (double)positiveCount / arr.Count;
     double negativeRatio = (double)negativeCount / arr.Count;
     double zeroRatio = (double)zeroCount / arr.Count;

     Console.WriteLine(positiveRatio.ToString("F6"));
     Console.WriteLine(negativeRatio.ToString("F6"));
     Console.WriteLine(zeroRatio.ToString("F6"));