Summary of large numerical problems in Java

Large numerical problems:

If the basic integers (for example: int, long) and the precision of the floating-point number are not sufficient for the dog, then it is possible to use the two classes in the Java.math package BigInteger (integers of arbitrary precision) and bigdecimal (floating-point numbers with arbitrary precision).

These two classes can realize the numeric value of one-time-length numbers

BigInteger a = biginteger.valueof (100);//convert 100 to a large number type integer

Use the valueof () method to convert a normal value to a large number

So then, how do you use large numbers to achieve numerical operations?

The addition method available in Java is:

BigInteger sum = A.add (b);//c = a + b;

BigInteger ji = a.multiply (B.add (biginteger.valueof (2)));//ji = A * (b + 2)

Note:

Unlike C + +, Java provides only string connections, overloads the + operator, Java does not provide overloaded functionality for operators, and does not give Java programmers the opportunity to write operator overloads in their own classes.

Number of calculated combinations:

c = c.multiply (Biginteger.valueof (n-i+1). Divide (biginteger.valueof (i)));//(n-i+1)/I

/** Description: There are n balls, one hand can grasp M, ask how many crawl way, N to 0 input to end the idea: the application of the Java.math package BigInteger class using a.multiply (b) to derive a*b product */import Java.math.biginteger;import Java.util.scanner;public class Main {public static void main (string[] args) {Scanner in = new S Canner (system.in); int n = 1,m;//The combined number of C (m,n) while (0!=n) {n = in.nextint (); m = In.nextint (); BigInteger C = biginteger.valueof (1); for (int i = 1;i<=m;i++) {c = c.multiply (biginteger.valueof (n-i+1)). Divide ( Biginteger.valueof (i));} System.out.println (c);}}

BigInteger:

BigInteger Add (BigInteger it)//summation//biginteger subtract (BigInteger it)//differential//biginteger multiply (BigInteger it)//quadrature/ /biginteger Divide (BigInteger it)//Business//biginteger mod (BigInteger it)//Find Model//int CompareTo (BigInteger it)//used to determine the size of two large numbers, The large number is equal to another large number of it, returns 0, is less than, returns a negative, is greater than the return positive//static biginteger.valueof (long x) static BigInteger valueOf (long xx)//A large integer that returns a value equal to XX

BigDecimal:

BigDecimal Add (BigDecimal it)//summation BigDecimal subtract (BigDecimal it)//differential BigDecimal multiply (BigDecimal it)// Quadrature BigDecimal mod (BigDecimal it)//Find a model

Exception:

BigDecimal Divide (BigDecimal it roundingmode mode) 5.0//rounding want to calculate must give rounding method, as for other rounding methods can refer to the API document static BigDecimal ValueOf (long x)///return value equals x large real number static BigDecimal valueOf (long x,int k)//Large real number with return value of x/(10 k-th square)

Summary of large numerical problems in Java