Large numbers< Java Programming
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The integer primitive type with the largest range of value is the
long, from -263 to 263-1. If you need greater or lesser values, you have to use the
BigInteger class in the package
BigInteger object can represent any integer (as large as the RAM on the computer can hold) as it is not mapped on a primitive type. Respectively, you need to use the
BigDecimal class for great decimal numbers.
However, as these perform much slower than primitive types, it is recommended to use primitive types when it is possible.
BigInteger class represents integers of almost any size. As with other objects, they need to be constructed. Unlike regular numbers, the
BigInteger represents an immutable object - methods in use by the
BigInteger class will return a new copy of a
To instantiate a
BigInteger, you can create it from either byte array, or from a string. For example:
|Code section 3.23: 1 quintillion, or 10^18. Too large to fit in a long.
1 BigInteger i = new BigInteger("1000000000000000000");
BigInteger cannot use the normal Java operators. They use the methods provided by the class.
|Code section 3.24: Multiplications and an addition.
1 BigInteger a = new BigInteger("3"); 2 BigInteger b = new BigInteger("4"); 3 4 // c = a^2 + b^2 5 BigInteger c = a.multiply(a).add(b.multiply(b));
|Code section 3.25: Conversion.
1 BigInteger aBigInteger = new BigInteger("3"); 2 long aLong = aBigInteger.longValue();
BigInteger class cannot handle decimal numbers. The
BigDecimal class represents a floating point value of arbitrary precision. It is composed of both a
BigInteger, and a scale value (represented by a 32-bit integer).