大数运算

1、判断是否为质数

static void Main(string[] args){
	Console.WriteLine("请输入一个很大的数字：");
	string bigNumber = Console.ReadLine();
	BigInteger bigInteger = BigInteger.Parse(bigNumber);
	bool isNumber=false;
	for (BigInteger i = 2; i < BigInteger.Pow(bigInteger, 2);i++ ){
		if (bigInteger % i == 0){
			isNumber = true;
			break;
		}
	}
	if (isNumber){
		Console.WriteLine("不是质数");
	}
	else{
		Console.WriteLine("是质数");
	}
	Console.ReadLine();
}

2、 实现两个大数的加减乘除

static void Main(string[] args){
Console.Write("请输入第一个大数字:");
	string bigNum1 = Console.ReadLine();
	BigInteger bigInt1 = BigInteger.Parse(bigNum1);

	Console.Write("请输入第二个大数字:");
	string bigNum2 = Console.ReadLine();
	BigInteger bigInt2 = BigInteger.Parse(bigNum2);
	Console.Write(Environment.NewLine);

	BigInteger addNum = bigInt1 + bigInt2;
	BigInteger subNum = bigInt1 - bigInt2;
	BigInteger purNum = bigInt1 * bigInt2;
	BigInteger divNum = bigInt1 / bigInt2;

	Console.WriteLine("两大数相加结果为：{0}",addNum);
	Console.WriteLine("两大数相减结果为：{0}",subNum);
	Console.WriteLine("两大数相乘结果为：{0}",purNum);
	Console.WriteLine("两大数相除结果为：{0}",divNum);

Console.ReadLine();
}