OPI_LR2011_ch3

61

= 5.2 – Character CharacterTest

= -

- .

5.2.2 7 Biglnteger

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+ Java f ,

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E i (

-@ @, Java API Biglnteger, i f java.math. D g @f Number, (, doubleValue(), floatValue(), intValue(), longValue(). byteValue() shortValue()

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.

• @@ 'f BigDecimal

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'f Biglnteger.

toByteArray() @f 'f . m g Biglnteger @@

+, @ 'f BigInteger:

–abs() – f 'f, i @ , i f 'f this;

–add(x) – this + ;

–and(x) – this & ;

–andNot(x) – this &(~ ) ;

–divide(x) – this / ;

–divideAndRemainder( ) – f 'f

Biglnteger, i g this ;

–gcd(x) – g , @,

'f this ;

–m ( ) – g 'f this ;

–min(x) – g 'f this ;

–mod(x) – g 'f this

;

–modInverse(x) – g ,

'f this, ;

–modPow(n, m) – g 'f this,

n, m ;

–multiply( ) – this * ;

–negate() – , i f 'f;

–not() – ~this ;

–r( ) – this | ;

–pow(n) – , i f 'f,

n ;

–remainder( ) – this % ;

–shiftLeft(n) – this « n ;

–shiftRight(n) – this » n;

–signum() – + sign(x) ;

–subtract(x) – this - x ;

63

– xor(x) – this ^ x.

5.3 ,

. 5.3 f f .

= 5.3 – Biglnteger BiglntegerTest

' 5.2. Biglnteger BiglntegerTest

import Java.math.Biglnteger; class BiglntegerTest{

public static void main(String[] args){

Biglnteger a = new Biglnteger("99999999999999999") ; Biglnteger b = new Biglnteger("88888888888888888888"); System.out.println("bits in a = " + a.bitLength()); System.out.println("bits in b = " + b.bitLength); System.out.println("a + b = " + a.add(b)); System.out.println("a & b = " + a.and(b)); System.out.println("a & ~b = " + a.andNot(b)); System.out.println("a / b = " + a.divide(b));

Biglnteger[] r = a.divideAndRemainder(b); System.out.println("a / b: q = " + r[0] + ", r = " + r[l]); System.out.println("gcd(a, b) = " + a.gcd(b));

64

System.out.println("max(a, b) = " + a.max(b)); System.out.printin("min(a, b) = " + a.min(b)); System.out.println("a mod b = " + a.mod(b)); System.out.println("I/a mod b = " + a.modlnverse(b)); System.out.println(" mod b = " + a.modPow(a, b)); System.out.println("a * b = " + a.multiply(b)); System.out.println("-a = " + a.negate());

System, out. println("~a = " + a.not()); System.out.println("a | b = " + a.or(b)); System.out.println(" 3 = " + a.pow(3)); System.out.println("a % b = " + a.remainder(b)); System.out.println("a « 3 = " + a.shiftLeft(3)}; System.out.println("a » 3 = " + a.shiftRight(3)); System.out.println("sign(a) = " + a.signum()); System.out.println("a - b = " + a.subtract(b)); System.out.println(" b = " + a.xor(b));

}

}

, i 5.2

Java.math.

5.2.3 7 Big Decimal

C BigDecimal g java.math.

C ( 'f f

: 'f BigInteger,

int.

:, 76.34862

7634862 'f Biglnteger, 5 int. ; , ( - +,

( integer.MAX_VALUE. = 'f BigDecimal f

,

:

–ROUND_CEILING – g ;

–ROUND_DOWN – , g

@ @;

–ROUND_FLOOR – g ;

–ROUND_HALF_DOWN – ( ,

f f g ;

–ROUND_HALF_EVEN – ( ,

f f ;

65

–ROOND_HALF_UP – ( ,

f f g ;

–ROUND_UNNECESSARY – f, i

, ;

–ROUND_UP – , g @

@.

BigDecimal :

–BigDecimal(Biglnteger bi) – 'f

bi, @f @;

–BigDecimal(Biglnteger mantissa, int scale) – f

mantissa scale 'f; i scale

, f ;

–BigDecimal(double d) – 'f

f d; i d Na, f

;

–BigDecimal(String val) – f val,

Java.

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f f , . .

+ f,

, ,

'f, , BigDecimal(0.1), , i f

'f, ( @. ? . 4.5. 5

( 'f , BigDecimal("0.1"), @f 1.

C doubleValue(), floatValue(), intValue(), longValue().

m g @@

. ? @ 'f BigDecimal. ;

f 'f BigDecimal, n - int,

r – , i

:

–abs() – @ 'f this ;

–add(x) – this + ;

–divide( , r) – this / r ;

–divide( , n, r) – this / @

r ;

–m ( ) – g this ;

66

–min(x) – g this ;

–movePointLeft(n) – n ;

–movePointRight(n) – n ;

–multiply( ) – this * ;

–negate() – f 'f ;

–scale() – f ;

–setscale(n) – @f n ;

–setscale(n, r) – @f n f

r ;

–signum() – , i f 'f;

–subtract( ) – this - ;

–toBiginteger() – , i f 'f; unScaledValue() – f .

' 5.3 f ,

. 5.4 – .

= 5.4 – BigDecimal BigDecimalTest

67

' 5.3. BigDecimal

BigDecimalTest

import java.math.*; class BigDecimalTest{

public static void main,( String [] args) {

BigDecimal x = new BigDecimal("-12345.67890123456789"); BigDecimal y = new BigDecimal("345.7896e-4");

BigDecimal z = new BigDecimal(new Biglnteger("123456789"),8); System.out.println("|x| = " + x.abs()); System.out.println("x + y = " + x.add(y));

System.out.println("x / y = " + x.divide(y, BigDecimal.ROUND__DOWN)); System.out.println("S/N = " +

x.divide(y, 6, BigDecimal.ROUND_HALF_EVEN)); System.out.println("max(x, y) = " + x.max(y)); System.out.println("min(x, y) = " + x.min(y)); System.out.println("x « 3 = " * x.movePointLeft(3)); System.out.println("x » 3 = " + x.mpvePQintRight(3)); System.out.println("x * y = " + x.multiply(y)); System.out.println("-x = " + x.negate()); System.out.println("scale of x = " + x.scale());

System.out.println("increase scale of x to 20 = " + x.setScale(20)); System.out.println("decrease scale of x to 10 = " +

x.setScale(10, BigDecimal.ROUND_HALF__UP)) ; System.out.println("sign(x) = " + x.signum()); System.out.println("x - y = " + x.subtract(y)}; System.out.println("round x = " + x.toBiglnteger()); System.out.println("mantissa of x = " + x.unscaledValue()); System.out.println("mantissa of 0.1 =\n= " +

new BigDecimal(0.1).unscaledValue()); } }

5.3 "9 ) 9 4

5.3.1.

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.

5.3.2? Java -

.

5.3.3? :

1.sin(x/n), tan(x/n)

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f,

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2.cos(x/n),ctan(x/n)

: long, float. ; , i

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f,

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5.3.4.+ .

5.3.5? .

5.4 !, #",

5.4.1; .

5.4.2.

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5.4.4; .

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5.5.1‘ - ?

5.5.2E - ?

5.5.3. ?

5.5.4. Boolean?

5.5.5. Character?

5.5.6: Character.

5.5.7. BigInteger?

5.5.8: BigInteger.

5.5.9. BigDecimal?

5.5.10: BigDecimal.

70

> 'f ..' -

new. C string f

' :

–string() - @f 'f ( ;

–string(String str) – 'f @f g,

f ;

–string(StringBuffer str) – 'f

BufferString;

–string(byte[] byteArray) – 'f @f

byteArray;

–string(char[] charArray) – 'f @f

charArray Unicode;

–string(byte[] byteArray, int offset, int count) – 'f @f

byteArray, i f offset

count ;

–string(char[] charArray, int offset, int count) – (,

f Unicode;

–string(byte[] byteArray, String encoding) – ,

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encoding ;

–string(byte[] byteArray, int offset, int count, String encoding) – ( , .

C , c[] @f s1,

, >=866, @f s2. : g,

@f s3 - . ' 6.1. >

class StringTest{

public static void main(String[] args){

String winLikeWin = null, winLikeDOS = null, winLikeUNIX = null; String dosLikeWin = null, dosLikeDOS = null, dosLikeUNIX = null; String unixLikeWin = null, unixLikeDOS = null, unixLikeUNIX = null; String msg = null;

byte[] byteCp!251 = { (byte)0x0,(byte)0xEE,(byte)0xFl, (byte)0xFl,(byte)0xES,(byte)0xFF };

byte[] byteCp866 = { (byte)0x90,(byte)0xAE,(byte)0x1, (byte)0xEl,(byte)0x8,(byte)0xEF };

byte[] byteKOISR =( (byte)0x2,(byte)0xCF,(byte)0x3,