总结——Java大数模板应用

Java大数模板应用

0.创建大数类

import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.Scanner;

Scanner cin=new Scanner(System.in);

BigInteger num1=new BigInteger("12345");
BigInteger num2=cin.nextBigInteger();

BigDecimal num3=new BigDecimal("123.45");
BigDecimal num4=cin.nextBigDecimal();

1.BigInteger(整数)

import java.math.BigInteger;

public class Main {
public static void main(String[] args) {
BigInteger num1=new BigInteger("12345");
BigInteger num2=new BigInteger("45");
//加法
System.out.println(num1.add(num2));
//减法
System.out.println(num1.subtract(num2));
//乘法
System.out.println(num1.multiply(num2));
//除法(相除取整)
System.out.println(num1.divide(num2));
//取余
System.out.println(num1.mod(num2));
//最大公约数GCD
System.out.println(num1.gcd(num2));
//取绝对值
System.out.println(num1.abs());
//取反
System.out.println(num1.negate());
//取最大值
System.out.println(num1.max(num2));
//取最小值
System.out.println(num1.min(num2));
//是否相等
System.out.println(num1.equals(num2));
}
}

2.BigDecimal(浮点数)

import java.math.BigDecimal;

public class Main {
public static void main(String[] args) {
BigDecimal num1=new BigDecimal("123.45");
BigDecimal num2=new BigDecimal("4.5");
//加法
System.out.println(num1.add(num2));
//减法
System.out.println(num1.subtract(num2));
//乘法
System.out.println(num1.multiply(num2));
//除法（在divide的时候就设置好要精确的小数位数和舍入模式）
System.out.println(num1.divide(num2,10,BigDecimal.ROUND_HALF_DOWN));
//取绝对值
System.out.println(num1.abs());
//取反
System.out.println(num1.negate());
//取最大值
System.out.println(num1.max(num2));
//取最小值
System.out.println(num1.min(num2));
//是否相等
System.out.println(num1.equals(num2));
//判断大小( > 返回1, < 返回-1)
System.out.println(num2.compareTo(num1));
}
}