Java 大數運算

import java.util.*;
import java.math.*;

public class BigNumberCount{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        String str;
  
        while( sc.hasNext() ){
            str = sc.nextLine();
            StringBuffer sb = new StringBuffer(str);
   
            String str1 = sb.substring(0, sb.indexOf(" "));
            sb.delete(0, sb.indexOf(" ")+1);
            String symbol = sb.substring(0, sb.indexOf(" "));
            String str2 = sb.substring(sb.indexOf(" ")+1, sb.length());
            
            BigInteger a = new BigInteger(str1);
            BigInteger b = new BigInteger(str2);
   
            switch( symbol.charAt(0) ){
                case '+':
                    System.out.println( a.add(b) );
                    break;
                case '-':
                    System.out.println( a.subtract(b) );
                    break;
                case '*':
                    System.out.println( a.multiply(b) );
                    break;
                case '/':
                    System.out.println( a.divide(b) );
                    break;
            }  
        }
    }
}

說明

直接使用Java.math底下的BigInteger類別實做

題目

大數運算

參考

超長整數運算（大數運算）