Random Probability Selection

int playersLeft = 100
int winners = 0

while (winners < 10)
    winners += (random.Next(playersLeft--)<(10-winners)) ? 1 : 0;

int prizes = 10;
for(int i = 100; i >= 1; i++)
{
  var result = random.Next(people);
  if(result < prizes)
  {
     Console.WriteLine("{0} won", i);
     prizes--;
  }
}

var winners = new HashSet<int>();
while(winners.Count < 10)
{
  var number = random.Next(100);
  if(!winners.Contains(number)) winners.Add(number);
}

for(i = 0; i < 100; i++)
{
  if(winners.Contains(i)) Console.WriteLine("{0} won!!!", i);
  else Console.WriteLine("{0} didn't win, sorry...", i);
}

int prizes = 10;
int people = 100;

while ( prizes > 0 ) {
   double probOfWin = (double) prizes / people;
   if ( random.NextDouble() <= probOfWin ) {
      prizes--;
   }
   people--;
}