JAVA核心技術（總結）——大數

BigInteger ：整數

BigInteger i = in.nextBigInteger();

BIgDecimal ： 浮點數

BigDecimal f = in.nextBigDecimal();

valyeOf : 將普通字符轉化爲大數

BigInteger a = BigInteger.valueOf(100);

add：相加

BigInteger c = a.add(b);//c = a + b

multiply：相乘

BigInteger d = a.multiply(b);//d = a * b

substact：相減

igInteger e = a.subtract(b);// e = a - b;

divide：相除

BigInteger g = b.divide(a);//g = b / a;

mod：取餘

BigInteger m = a.mod(b);//m = a % b;

compareTo：比較

int compare1 = a.compareTo(a);//a等於a，結果爲0
int compare2 = a.compareTo(b);//a小於b，結果爲負
int compare3 = b.compareTo(a);//b大於a，結果爲正

相關實驗代碼如下：

import java.math.BigInteger;
import java.util.*;
import java.io.*;
import java.math.*;

public class BigNumber
{
    public static void main(String args[])
    {
    	Scanner in = new Scanner(System.in);
    	BigInteger i = in.nextBigInteger();
    	BigDecimal f = in.nextBigDecimal();
        BigInteger a = BigInteger.valueOf(100);
        BigInteger b = BigInteger.valueOf(200);
        BigInteger c = a.add(b);//c = a + b
        BigInteger d = a.multiply(b);//d = a * b
        BigInteger e = a.subtract(b);// e = a - b;
        BigInteger g = b.divide(a);//g = b / a;
        BigInteger m = a.mod(b);//m = a % b;
        int compare1 = a.compareTo(a);//a等於a，結果爲0
        int compare2 = a.compareTo(b);//a小於b，結果爲負
        int compare3 = b.compareTo(a);//b大於a，結果爲正
        System.out.println(i);
        System.out.println(f);
        System.out.println(a);
        System.out.println(b);
        System.out.println(c);
        System.out.println(d);
        System.out.println(e);
        System.out.println(g);
        System.out.println(m);
        System.out.println(compare1);
        System.out.println(compare2);
        System.out.println(compare3);
    }
}