BigInteger(long) has private access in BigInteger

Question

I am trying to store a big calculation in a BigInteger instance. I tried this :

BigInteger answer=new BigInteger(2+3);

and got the following error :

temp.java:17: error: BigInteger(long) has private access in BigInteger
                        BigInteger answer=new BigInteger(2+3);
                                          ^
1 error

I know that instead of "2+3" there should be a string value. But i don't know how to satisfy that condition(assuming that i don't how much 2+3 is). Please tell me how to assign a calculated value to BigInteger object(assign 2+3 to BigInteger answer).

Answer 1

If you want to perform the arithmetic using BigInteger , you should create a BigInteger for each value and then use BigInteger.add . However, you don't need to use strings to do that. You may want to if your input is already a string and it might be long, but if you've already got a long , you can use BigInteger.valueOf . For example:

BigInteger answer = BigInteger.valueOf(2).add(BigInteger.valueOf(3));

I certainly wouldn't convert a long into a String just to then pass it into the BigInteger constructor.

Answer 2

You could just use BigInteger's add(...) method:

BigInteger answer = new BigInteger("2").add(new BigInteger("3"));

No worries about overflow with this solution.