public static void Main()
int[] allgrades = new int [5] {5,10,15,20,25};
for (int i = 0; i < allgrades.Length - 1 ; i++)
for ( int j = i + 1 ; j < allgrades.Length - 1; i++)
if (allgrades[j] < allgrades[pos_min])
allgrades[i] = allgrades[pos_min];
allgrades[pos_min = temp;
Console.WriteLine(allgrades);