• • 题目描述
  • Java 大整数
    • 分析
    • 代码
      • 加
      • 减
      • 乘
      • 除
    • 时间复杂度
  • 参考文章
    • java 高精度 四则运算

java之BigDecimal

 num1 = num1.divide(num2,10,BigDecimal.ROUND_HALF_EVEN); 
    System.out.println(num1);

算阶乘时也可用；

需要转化一下

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1 int n = cin.nextInt() ;
2         BigInteger m = BigInteger.valueOf(1) ;
3         for(int i = 1;i<=n;i++){
4             m = m.multiply(BigInteger.valueOf(i)) ;//int 整形转化为 BigInteger  进行计算
5         }
6         System.out.println(m);

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//输入两个大数进行加法运算 add() 相加

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 1 import java.util.Scanner;
 2 import java.math.BigInteger;
 3 public class dashu {
 4     public static void main(String[] args) {
 5         Scanner input = new Scanner(System.in);
 6         BigInteger a,b;
 7             a=input.nextBigInteger();
 8             b=input.nextBigInteger();
 9             System.out.println(a.add(b));
10         }
11     }

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//输入两个大数相减 subtract () 相减

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 1 import java.util.*;
 2 import java.math.BigInteger;
 3 public class dashu {
 4     public static void main(String args[]) {
 5         Scanner input = new Scanner(System.in);
 6         BigInteger num1 = input.nextBigInteger();
 7         BigInteger num2 = input.nextBigInteger();
 8         System.out.println(num1.subtract(num2));
 9     }
10 }
11         

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//输入两个大数相乘 mulitiply () 相乘

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 1 import java.util.* ;
 2 import java.math.BigInteger ;
 3 public class dashu {
 4     public static void main(String[] args) {
 5         Scanner input = new Scanner(System.in) ;
 6         BigInteger m,n;
 7         m=input.nextBigInteger();
 8         n=input.nextBigInteger();
 9             m = m.multiply(n) ;
10         System.out.println(m);
11     }
12 }

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//两个大数相除 divide() 相除 remainder() 余数

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 1 import java.util.*;
 2 import java.math.BigInteger;
 3 public class dashu {
 4     public static void main(String args[]) {
 5         Scanner input = new Scanner(System.in);
 6         BigInteger num1 = input.nextBigInteger();
 7         BigInteger num2 = input.nextBigInteger();
 8         System.out.println(num1.divide(num2));//相除
 9         System.out.println(num1.remainder(num2));//余数
10     }
11 }
12         

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