Java——BigInteger

BigInteger

java中long型为最大整数类型,对于超过long型的数据如何去表示呢.在Java的世界中,超过long型的整数已经不能被称为整数了,它们被封装成BigInteger对象.在BigInteger类中,实现四则运算都是方法来实现,并不是采用运算符.

  BigInteger类的构造方法:

BigInteger b = new BigInteger(str);

  构造方法中,采用字符串的形式给出整数

四则运算代码：

public static void main(String[] args) {

          //大数据封装为BigInteger对象
          BigInteger big1 = new BigInteger("12345678909876543210");
          BigInteger big2 = new BigInteger("98765432101234567890");

          //add实现加法运算
          BigInteger bigAdd = big1.add(big2);

          //subtract实现减法运算
          BigInteger bigSub = big1.subtract(big2);

          //multiply实现乘法运算
          BigInteger bigMul = big1.multiply(big2);

          //divide实现除法运算
          BigInteger bigDiv = big2.divide(big1);

}

 biginteger怎么比较大小

compareTo方法来比较，小于则返回-1，等于则返回0，大于则返回1

BigInteger a1 = new BigInteger("10");
BigInteger a2 = new BigInteger("20");
BigInteger a3 = new BigInteger("20");
int b1 = a1.compareTo(a2);//b1为-1
int b2 = a2.compareTo(a1);//b2为1
int b3 = a2.compareTo(a3);//b3为0