java - 如何在 Java 中添加非常大的值？

Question

我尝试了下面的代码，但出现错误。我将如何将两个表示为字符串的大值添加在一起？

public class LargeAddition {

    static String testcase1 = "987659876598765";
    static String testcase2 = "9999999999999999999999999988888888888";//can we add this kind of large num

    public static void main(String args[]){
        LargeAddition testInstance = new LargeAddition();
        String result = testInstance.add(testcase1,testcase2);
        System.out.println("Result : "+result);

    }

    //write your code here
    public String add(String str1, String str2){
        Long num=000000000000000L;
        //String str="";
        num=Long.parseLong(str1)+Long.parseLong(str2);
        //String str=num.toString();

        return num.toString();
    }
}

Answer 1

使用BigInteger，Long是这些值的缩写。

public static String add(String str1, String str2) {
    BigInteger big1 = new BigInteger(str1);
    BigInteger big2 = new BigInteger(str2);

    final BigInteger num = big1.add(big2);
    return num.toString();
}