其实除了Python,Ruby外,Java也自带高精,只不过被封装在类里.Java有两个高精类:BigInteger和BigDecimal,分别是高精度整数和高精度小数.本文来简单介绍一下BigInteger类.

构造

BigInteger类只能从String构造.如,

BigInteger a = new BigInteger("233") ;

如果要用Scanner读入一个BigInteger,可以这么写:

Scanner scan = new Scanner(System.in) ;

BigInteger a = new BigInteger(scan.next()) ;

函数

因为Java不支持重载运算符,所以所有的运算都由函数来实现.

BigInteger add(BigInteger val) //求和

BigInteger subtract(BigInteger val) //相减

BigInteger multiply(BigInteger val) //求积

BigInteger divide(BigInteger val) //求商

BigInteger mod(BigInteger val) //取模

BigInteger remainder(BigInteger val) //求余

BigInteger pow(int exponent) //求幂

BigInteger abs() //绝对值

BigInteger gcd(BigInteger val) //求gcd

BigInteger max(BigInteger val) //求较大值

BigInteger min(BigInteger val) //求较小值

BigInteger negate() //相反数

BigInteger leftShift(int n) //左移

BigInteger rightShift(int n) //右移

BigInteger and(BigInteger val) //求与

BigInteger andNot(BigInteger val) //求与+取反(与非)

BigInteger or(BigInteger val) //求或

BigInteger xor(BigInteger val) //求异或

BigInteger not() //取反

int intValue() //转int

long longValue() //转long

double doubleValue() //转double

float floatValue() /转float

byte[] toByteArray(BigInteger val) //转byte数组(底层实现是由byte数组的反码构成的)

String toString() //转字符串

最后说一句,BigInteger在java.math库中.

Code

import java.util.* ;

import java.io.* ;

import java.math.BigInteger;

public class Main {

public static void main(String[] args) {

Scanner scan = new Scanner(System.in) ;

BigInteger a = new BigInteger(scan.next()), b = new BigInteger(scan.next()) ;

System.out.println(a.add(b)) ;

System.out.println(a.subtract(b)) ;

System.out.println(a.multiply(b)) ;

System.out.println(a.divide(b)) ;

System.out.println(a.mod(b)) ;

}

}