The BigInteger class in Java is a useful tool for performing mathematical operations that involve very large integer calculations. These calculations are beyond the limit of all available primitive data types. This class has a large method library and is frequently used in competitive programming.
To use BigInteger, first, you need to initialize the values. If you have an integer, you can initialize it by using the BigInteger.valueOf() method. If you have a string, you can initialize it by using the new BigInteger() method. There are also some constants defined in the BigInteger class, such as BigInteger.ZERO, BigInteger.ONE, and BigInteger.TEN, which can be used for ease of initialization.
Once the values are initialized, you can perform mathematical operations such as addition, subtraction, multiplication, division, and remainder. However, all these functions take BigInteger as their argument. Therefore, if you want to perform operations with integers or strings, you need to convert them to BigInteger before passing them to the functions.
You can also extract the value from a BigInteger using the intValue(), longValue(), or toString() method. Additionally, you can compare BigInteger values using the compareTo() method, which returns -1 (less than), 0 (equal), or 1 (greater than) according to the values. You can also use the equals() method to check for equality.
The BigInteger class has many methods for performing various operations, such as add(), subtract(), multiply(), divide(), remainder(), abs(), and pow(). Some methods return a new BigInteger, while others modify the existing one. For example, the add() method returns a BigInteger whose value is (this + val), while the clearBit() method returns a BigInteger whose value is equivalent to this BigInteger with the designated bit cleared.
In conclusion, the BigInteger class in Java is a useful tool for performing mathematical operations involving large integer calculations. It provides a wide range of methods that can be used to perform various operations.