percentage random c#
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// Some c`lass or struct for represent items you want to roulette
public class Item
{
public string name; // not only string, any type of data
public int chance; // chance of getting this Item
}
public class ProportionalWheelSelection
{
public static Random rnd = new Random();
// Static method for using from anywhere. You can make its overload for accepting not only List, but arrays also:
// public static Item SelectItem (Item[] items)...
public static Item SelectItem(List<Item> items)
{
// Calculate the summa of all portions.
int poolSize = 0;
for (int i = 0; i < items.Count; i++)
{
poolSize += items[i].chance;
}
// Get a random integer from 0 to PoolSize.
int randomNumber = rnd.Next(0, poolSize) + 1;
// Detect the item, which corresponds to current random number.
int accumulatedProbability = 0;
for (int i = 0; i < items.Count; i++)
{
accumulatedProbability += items[i].chance;
if (randomNumber <= accumulatedProbability)
return items[i];
}
return null; // this code will never come while you use this programm right :)
}
}
// Example of using somewhere in your program:
static void Main(string[] args)
{
List<Item> items = new List<Item>();
items.Add(new Item() { name = "Anna", chance = 100});
items.Add(new Item() { name = "Alex", chance = 125});
items.Add(new Item() { name = "Dog", chance = 50});
items.Add(new Item() { name = "Cat", chance = 35});
Item newItem = ProportionalWheelSelection.SelectItem(items);
}