Example
using System.Diagnostics.Contracts;
public int IncrementByRandomAmount(int input)
{
Contract.Requires<ArgumentNullException>(input != null); // Don't allow null parameter.
Contract.Requires<ArgumentOutOfRangeException>(input < int.MaxValue); // We can't do anything if we're given int.MaxValue.
Contract.Ensures(Contract.Result<int>() > input); // Return value will be greater than input value.
Random rnd = new Random();
input += rnd.Next(1, 13); // Creates a number between 1 and 12 and adds it to input.
return input;
}
