Twinone Twinone - 3 years ago 255
Java Question

How do I convert a String to a BigInteger?

I'm trying to read some really big numbers from standard input and add them together.

However, to add to BigInteger, I need to use

BigInteger.valueOf(long);
:

private BigInteger sum = BigInteger.valueOf(0);

private void sum(String newNumber) {
// BigInteger is immutable, reassign the variable:
sum = sum.add(BigInteger.valueOf(Long.parseLong(newNumber)));
}


That works fine, but as the
BigInteger.valueOf()
only takes a
long
, I cannot add numbers greater than
long
's max value (9223372036854775807).

Whenever I try to add 9223372036854775808 or more, I get a NumberFormatException (which is completely expected).

Is there something like
BigInteger.parseBigInteger(String)
?

Answer Source

Using the constructor

BigInteger(String val)

Translates the decimal String representation of a BigInteger into a BigInteger.

Javadoc

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