title: C# cannot convert Int to Double
body: <p>I get the error converting <code>Int</code> to <code>Double</code>, my next line <code>Average[y] = Average[y] + Students[i].Marks;</code> is not working either. So how can convert <code>int[]</code> to <code>double[]</code>?</p>
  
  <pre><code>public static double[] Averages(StudentMarks[] Students, int amount, string[] DifferentGroups, int GroupAmount, out double[] Average)
      {
          Average = new double[Max];
          int y = 0;
          int CountGroups = 0;
          //int sum = 0;
          for (int i = 0; i &lt; amount; i++)
          {
              if (Students[i].Group == DifferentGroups[y])
              {
                  Convert.ToDouble(Students[i].Marks);
                  //Average[y] = Average[y] + Students[i].Marks;
              }
          }
          return Average;
      }
  </code></pre>
  
  <p>The main:</p>
  
  <pre><code> static void Main(string[] args)
      {
          int amount;
          StudentMarks[] Students;
          string[] DifferentGroups;
          int GroupAmount;
          double[] Average;
          ReadData(out Students, out amount);
          DifferentGroups = FindDifferentGroups(Students, amount, out DifferentGroups, out GroupAmount);
          Average = Averages(Students, amount, DifferentGroups, GroupAmount, out Average);
  </code></pre>
  
  <p>Class:</p>
  
  <pre><code>        public const int Max = 50;
      public string Surname { get; set; }
      public string Name { get; set; }
      public string Group { get; set; }
      public int AmountOfMarks { get; set; }
      public int[] Marks { get; set; }
  </code></pre>
  
  <p>So Student[i].Marks is Array.</p>