java大数模板

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

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

public class Main {//类必须是Main
public static void main(String args[])
{
Scanner scan = new Scanner(System.in);
int T;
T = scan.nextInt();
while(T > 0)
{
BigInteger a;
BigInteger b = new BigInteger("123");//大数的初始化，括号里面是字符串
a = scan.nextBigInteger();//读入一个大数
a = a.add(b);//相当与a = a + b,注意a.add(b)不会改变a的值
a = a.subtract(b);//相当于a = a - b;
a = a.divide(b);//a = a / b
a.compareTo(b);//大数的比较函数，如果a > b,返回1，a = b,返回0，a < b返回-1
System.out.println(a)//输出大数
}
return;
}
}