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　　本文是在我的另一个博客中copy过来的，感觉博客园比较适合写代码就迁过来了

　　好久都没有写过日志了，前两天去面试，看到面试题中有关于大数操作的问题，所以回来以后就总结了一下，供笔试着还有要参加acm的同学做一些参考。

先说一下大数相加：

1 package com.my.lucene; 2  3   4 import java.math.BigInteger; 5  6   7 public class test { 8 public static void main(String[] args) { 9 String a = "15432321321223123231321"; String  b = "2121212121214354343544354354";10 BigInteger bg = new BigInteger(a);11 BigInteger gBigInteger= bg.add(new BigInteger(b));12 System.out.println(gBigInteger);13 }14 }15 大数相减： 16 package com.my.lucene;17 18 19 import java.math.BigInteger;20 21 22 public class test {23 public static void main(String[] args) {24 String a = "15432321321223123231321"; String  b = "2121212121214354343544354354";25 BigInteger bg = new BigInteger(a);26 BigInteger gBigInteger= bg.subtract(new BigInteger(b));27 System.out.println(gBigInteger);28 }29 }

 

大数相乘：

1 package com.my.lucene; 2  3  4 import java.math.BigInteger; 5  6  7 public class test { 8 public static void main(String[] args) { 9 String a = "15432321321223123231321"; String  b = "2121212121214354343544354354";10 BigInteger bg = new BigInteger(a);11 BigInteger gBigInteger= bg.multiply(new BigInteger(b));12 System.out.println(gBigInteger);13 }14 }15 大数除法：16 package com.my.lucene;17 18 19 import java.math.BigInteger;20 21 22 public class test {23 public static void main(String[] args) {24 String a = "15432321321223123231321"; String  b = "2121212121214354343544354354";25 BigInteger bg = new BigInteger(a);26 BigInteger gBigInteger= bg.divide(new BigInteger(b));27 System.out.println(gBigInteger);28 }29 }

大数相减：

1 package com.my.lucene; 2  3  4 import java.math.BigInteger; 5  6  7 public class test { 8 public static void main(String[] args) { 9 String a = "15432321321223123231321"; String  b = "2121212121214354343544354354";10 BigInteger bg = new BigInteger(a);11 BigInteger gBigInteger= bg.subtract(new BigInteger(b));12 System.out.println(gBigInteger);13 }14 }