Math

Quersumme

static int Checksum(int num)  
{  
    int sum = 0;  
    while (num > 0)  
    {        
	    sum += num % 10;  
        num /= 10;  
    }  
    return sum;  
}

---

GGT

static int GetGreatestCommonDivisor(int a, int b)
{
    if (b == 0)
        return a;
    else return GetGreatestCommonDivisor(b, a % b);
}

---

Gaußsche Summenformel

static int GaussianSum(int n)
{
	result = (n * (n + 1)) / 2;
}

---

Fibonacci Zahlen

static int Fibonacci(int n)
{
	if (n <= 0)
		return 0;
	else if (n == 1)
		return 1;
	else
		return Fibonacci(n - 1) + Fibonacci(n - 2);
}

---

Faktorial-Berechnung

static int Factorial(int n):
    if (n == 0)
        return 0;
    elif (n == 1)
        return 1;
    else
        return n * Factorial(n - 1);

---

Primzahl bestimmen

static bool IsPrime(int number) 
{ 
	if (number < 2) return false; 
	if (number == 2 || number == 3) return true; 
	if (number % 2 == 0 || number % 3 == 0) return false;
		
	for (int i = 5; i * i <= number; i += 6) 
	{ 
		if (number % i == 0 || number % (i + 2) == 0) 
			return false; 
	} 
	return true; 
}