\(\newcommand{\footnotename}{footnote}\) \(\def \LWRfootnote {1}\) \(\newcommand {\footnote }[2][\LWRfootnote ]{{}^{\mathrm {#1}}}\) \(\newcommand {\footnotemark }[1][\LWRfootnote ]{{}^{\mathrm {#1}}}\) \(\let \LWRorighspace \hspace \) \(\renewcommand {\hspace }{\ifstar \LWRorighspace \LWRorighspace }\) \(\newcommand {\TextOrMath }[2]{#2}\) \(\newcommand {\mathnormal }[1]{{#1}}\) \(\newcommand \ensuremath [1]{#1}\) \(\newcommand {\LWRframebox }[2][]{\fbox {#2}} \newcommand {\framebox }[1][]{\LWRframebox } \) \(\newcommand {\setlength }[2]{}\) \(\newcommand {\addtolength }[2]{}\) \(\newcommand {\setcounter }[2]{}\) \(\newcommand {\addtocounter }[2]{}\) \(\newcommand {\arabic }[1]{}\) \(\newcommand {\number }[1]{}\) \(\newcommand {\noalign }[1]{\text {#1}\notag \\}\) \(\newcommand {\cline }[1]{}\) \(\newcommand {\directlua }[1]{\text {(directlua)}}\) \(\newcommand {\luatexdirectlua }[1]{\text {(directlua)}}\) \(\newcommand {\protect }{}\) \(\def \LWRabsorbnumber #1 {}\) \(\def \LWRabsorbquotenumber "#1 {}\) \(\newcommand {\LWRabsorboption }[1][]{}\) \(\newcommand {\LWRabsorbtwooptions }[1][]{\LWRabsorboption }\) \(\def \mathchar {\ifnextchar "\LWRabsorbquotenumber \LWRabsorbnumber }\) \(\def \mathcode #1={\mathchar }\) \(\let \delcode \mathcode \) \(\let \delimiter \mathchar \) \(\def \oe {\unicode {x0153}}\) \(\def \OE {\unicode {x0152}}\) \(\def \ae {\unicode {x00E6}}\) \(\def \AE {\unicode {x00C6}}\) \(\def \aa {\unicode {x00E5}}\) \(\def \AA {\unicode {x00C5}}\) \(\def \o {\unicode {x00F8}}\) \(\def \O {\unicode {x00D8}}\) \(\def \l {\unicode {x0142}}\) \(\def \L {\unicode {x0141}}\) \(\def \ss {\unicode {x00DF}}\) \(\def \SS {\unicode {x1E9E}}\) \(\def \dag {\unicode {x2020}}\) \(\def \ddag {\unicode {x2021}}\) \(\def \P {\unicode {x00B6}}\) \(\def \copyright {\unicode {x00A9}}\) \(\def \pounds {\unicode {x00A3}}\) \(\let \LWRref \ref \) \(\renewcommand {\ref }{\ifstar \LWRref \LWRref }\) \( \newcommand {\multicolumn }[3]{#3}\) \(\require {textcomp}\) \(\newcommand {\intertext }[1]{\text {#1}\notag \\}\) \(\let \Hat \hat \) \(\let \Check \check \) \(\let \Tilde \tilde \) \(\let \Acute \acute \) \(\let \Grave \grave \) \(\let \Dot \dot \) \(\let \Ddot \ddot \) \(\let \Breve \breve \) \(\let \Bar \bar \) \(\let \Vec \vec \) \(\renewcommand {\vec }{\boldsymbol }\) \(\newcommand {\Edge }{\ensuremath {\,\textemdash \,}}\) \(\newcommand \Const [1]{\text {\textsf {#1}}}\) \(\DeclareMathOperator {\lerp }{lerp}\) \(\DeclareMathOperator {\bitlen }{bitlen}\) \(\DeclareMathOperator {\sign }{sign}\) \(\newcommand {\I }{\mathrm {i}}\) \(\newcommand \AND {\mathbin {\&}}\) \(\newcommand \OR {\mathbin {|}}\) \(\newcommand \XOR {\mathbin {{}^{\wedge }}}\) \(\newcommand \shl {\ll }\) \(\newcommand \shr {\ggg }\) \(\newcommand \asr {\gg }\) \(\newcommand \NOT {\ensuremath {\mathord {\sim }}}\) \(\newcommand {\isep }{\mathrel {{.}\,{.}}}\) \(\newcommand {\Id }[1]{\mathit {#1}}\) \(\newcommand {\const }[1]{\mathsf {#1}}\) \(\newcommand {\algorithmname }[1]{\text {\textsc {#1}}}\) \(\newcommand {\bits }[1]{\text {#1}}\) \(\newcommand {\hexa }[1]{\mathtt {0x#1}}\) \(\newcommand {\num }[1]{#1}\) \(\newcommand {\qed }{\quad \square }\) \(\newcommand {\idiv }[2]{\lfloor #1/#2\rfloor }\) \(\newcommand \attribdot {\ensuremath {\mkern 1.5mu.\mkern 1.5mu}}\) \(\newcommand \attribxr [2]{#1\attribdot \text {#2}}\) \(\newcommand \attribir [2]{\Id {#1}\attribdot \text {#2}}\) \(\newcommand \attribii [2]{\Id {#1}\attribdot \Id {#2}}\) \(\newcommand \textsc [1]{#1}\) \(\require {colortbl}\) \(\let \LWRorigcolumncolor \columncolor \) \(\renewcommand {\columncolor }[2][named]{\LWRorigcolumncolor [#1]{#2}\LWRabsorbtwooptions }\) \(\let \LWRorigrowcolor \rowcolor \) \(\renewcommand {\rowcolor }[2][named]{\LWRorigrowcolor [#1]{#2}\LWRabsorbtwooptions }\) \(\let \LWRorigcellcolor \cellcolor \) \(\renewcommand {\cellcolor }[2][named]{\LWRorigcellcolor [#1]{#2}\LWRabsorbtwooptions }\) \(\newcommand {\tcbset }[1]{}\) \(\newcommand {\tcbsetforeverylayer }[1]{}\) \(\newcommand {\tcbox }[2][]{\boxed {\text {#2}}}\) \(\newcommand {\tcboxfit }[2][]{\boxed {#2}}\) \(\newcommand {\tcblower }{}\) \(\newcommand {\tcbline }{}\) \(\newcommand {\tcbtitle }{}\) \(\newcommand {\tcbsubtitle [2][]{\mathrm {#2}}}\) \(\newcommand {\tcboxmath }[2][]{\boxed {#2}}\) \(\newcommand {\tcbhighmath }[2][]{\boxed {#2}}\) \(\newcommand {\toprule }[1][]{\hline }\) \(\let \midrule \toprule \) \(\let \bottomrule \toprule \) \(\def \LWRbooktabscmidruleparen (#1)#2{}\) \(\newcommand {\LWRbooktabscmidrulenoparen }[1]{}\) \(\newcommand {\cmidrule }[1][]{\ifnextchar (\LWRbooktabscmidruleparen \LWRbooktabscmidrulenoparen }\) \(\newcommand {\morecmidrules }{}\) \(\newcommand {\specialrule }[3]{\hline }\) \(\newcommand {\addlinespace }[1][]{}\) \(\newcommand {\LWRsubmultirow }[2][]{#2}\) \(\newcommand {\LWRmultirow }[2][]{\LWRsubmultirow }\) \(\newcommand {\multirow }[2][]{\LWRmultirow }\) \(\newcommand {\mrowcell }{}\) \(\newcommand {\mcolrowcell }{}\) \(\newcommand {\STneed }[1]{}\) \(\newcommand {\LWRldelimtwo }[1][]{\text {#1}~\LWRbigdelim }\) \(\newcommand {\LWRldelimone }[2][]{\LWRldelimtwo }\) \(\def \ldelim #1#2{\def \LWRbigdelim {#1}\LWRldelimone }\) \(\newcommand {\LWRrdelimtwo }[1][]{\LWRbigdelim ~\text {#1}}\) \(\newcommand {\LWRrdelimone }[2][]{\LWRrdelimtwo }\) \(\def \rdelim #1#2{\def \LWRbigdelim {#1}\LWRrdelimone }\) \(\let \symnormal \mathit \) \(\let \symliteral \mathrm \) \(\let \symbb \mathbb \) \(\let \symbbit \mathbb \) \(\let \symcal \mathcal \) \(\let \symscr \mathscr \) \(\let \symfrak \mathfrak \) \(\let \symsfup \mathsf \) \(\let \symsfit \mathit \) \(\let \symbfsf \mathbf \) \(\let \symbfup \mathbf \) \(\newcommand {\symbfit }[1]{\boldsymbol {#1}}\) \(\let \symbfcal \mathcal \) \(\let \symbfscr \mathscr \) \(\let \symbffrak \mathfrak \) \(\let \symbfsfup \mathbf \) \(\newcommand {\symbfsfit }[1]{\boldsymbol {#1}}\) \(\let \symup \mathrm \) \(\let \symbf \mathbf \) \(\let \symit \mathit \) \(\let \symsf \symsfit \) \(\let \symtt \mathtt \) \(\let \symbffrac \mathbffrac \) \(\newcommand {\mathfence }[1]{\mathord {#1}}\) \(\newcommand {\mathover }[1]{#1}\) \(\newcommand {\mathunder }[1]{#1}\) \(\newcommand {\mathaccent }[1]{#1}\) \(\newcommand {\mathbotaccent }[1]{#1}\) \(\newcommand {\mathalpha }[1]{\mathord {#1}}\) \(\def\Alpha{\unicode{x1D6E2}}\) \(\def\Beta{\unicode{x1D6E3}}\) \(\def\Gamma{\unicode{x1D6E4}}\) \(\def\Digamma{\mathit{\unicode{x03DC}}}\) \(\def\Delta{\unicode{x1D6E5}}\) \(\def\Epsilon{\unicode{x1D6E6}}\) \(\def\Zeta{\unicode{x1D6E7}}\) \(\def\Eta{\unicode{x1D6E8}}\) \(\def\Theta{\unicode{x1D6E9}}\) \(\def\Vartheta{\unicode{x1D6F3}}\) \(\def\Iota{\unicode{x1D6EA}}\) \(\def\Kappa{\unicode{x1D6EB}}\) \(\def\Lambda{\unicode{x1D6EC}}\) \(\def\Mu{\unicode{x1D6ED}}\) \(\def\Nu{\unicode{x1D6EE}}\) \(\def\Xi{\unicode{x1D6EF}}\) \(\def\Omicron{\unicode{x1D6F0}}\) \(\def\Pi{\unicode{x1D6F1}}\) \(\def\Rho{\unicode{x1D6F2}}\) \(\def\Sigma{\unicode{x1D6F4}}\) \(\def\Tau{\unicode{x1D6F5}}\) \(\def\Upsilon{\unicode{x1D6F6}}\) \(\def\Phi{\unicode{x1D6F7}}\) \(\def\Chi{\unicode{x1D6F8}}\) \(\def\Psi{\unicode{x1D6F9}}\) \(\def\Omega{\unicode{x1D6FA}}\) \(\def\alpha{\unicode{x1D6FC}}\) \(\def\beta{\unicode{x1D6FD}}\) \(\def\varbeta{\unicode{x03D0}}\) \(\def\gamma{\unicode{x1D6FE}}\) \(\def\digamma{\mathit{\unicode{x03DD}}}\) \(\def\delta{\unicode{x1D6FF}}\) \(\def\epsilon{\unicode{x1D716}}\) \(\def\varepsilon{\unicode{x1D700}}\) \(\def\zeta{\unicode{x1D701}}\) \(\def\eta{\unicode{x1D702}}\) \(\def\theta{\unicode{x1D703}}\) \(\def\vartheta{\unicode{x1D717}}\) \(\def\iota{\unicode{x1D704}}\) \(\def\kappa{\unicode{x1D705}}\) \(\def\varkappa{\unicode{x1D718}}\) \(\def\lambda{\unicode{x1D706}}\) \(\def\mu{\unicode{x1D707}}\) \(\def\nu{\unicode{x1D708}}\) \(\def\xi{\unicode{x1D709}}\) \(\def\omicron{\unicode{x1D70A}}\) \(\def\pi{\unicode{x1D70B}}\) \(\def\varpi{\unicode{x1D71B}}\) \(\def\rho{\unicode{x1D70C}}\) \(\def\varrho{\unicode{x1D71A}}\) \(\def\sigma{\unicode{x1D70E}}\) \(\def\varsigma{\unicode{x1D70D}}\) \(\def\tau{\unicode{x1D70F}}\) \(\def\upsilon{\unicode{x1D710}}\) \(\def\phi{\unicode{x1D719}}\) \(\def\varphi{\unicode{x1D711}}\) \(\def\chi{\unicode{x1D712}}\) \(\def\psi{\unicode{x1D713}}\) \(\def\omega{\unicode{x1D714}}\) \(\def\upAlpha{\unicode{x0391}}\) \(\def\upBeta{\unicode{x0392}}\) \(\def\upGamma{\unicode{x0393}}\) \(\def\upDigamma{\unicode{x03DC}}\) \(\def\upDelta{\unicode{x0394}}\) \(\def\upEpsilon{\unicode{x0395}}\) \(\def\upZeta{\unicode{x0396}}\) \(\def\upEta{\unicode{x0397}}\) \(\def\upTheta{\unicode{x0398}}\) \(\def\upVartheta{\unicode{x03F4}}\) \(\def\upIota{\unicode{x0399}}\) \(\def\upKappa{\unicode{x039A}}\) \(\def\upLambda{\unicode{x039B}}\) \(\def\upMu{\unicode{x039C}}\) \(\def\upNu{\unicode{x039D}}\) \(\def\upXi{\unicode{x039E}}\) \(\def\upOmicron{\unicode{x039F}}\) \(\def\upPi{\unicode{x03A0}}\) \(\def\upVarpi{\unicode{x03D6}}\) \(\def\upRho{\unicode{x03A1}}\) \(\def\upSigma{\unicode{x03A3}}\) \(\def\upTau{\unicode{x03A4}}\) \(\def\upUpsilon{\unicode{x03A5}}\) \(\def\upPhi{\unicode{x03A6}}\) \(\def\upChi{\unicode{x03A7}}\) \(\def\upPsi{\unicode{x03A8}}\) \(\def\upOmega{\unicode{x03A9}}\) \(\def\itAlpha{\unicode{x1D6E2}}\) \(\def\itBeta{\unicode{x1D6E3}}\) \(\def\itGamma{\unicode{x1D6E4}}\) \(\def\itDigamma{\mathit{\unicode{x03DC}}}\) \(\def\itDelta{\unicode{x1D6E5}}\) \(\def\itEpsilon{\unicode{x1D6E6}}\) \(\def\itZeta{\unicode{x1D6E7}}\) \(\def\itEta{\unicode{x1D6E8}}\) \(\def\itTheta{\unicode{x1D6E9}}\) \(\def\itVartheta{\unicode{x1D6F3}}\) \(\def\itIota{\unicode{x1D6EA}}\) \(\def\itKappa{\unicode{x1D6EB}}\) \(\def\itLambda{\unicode{x1D6EC}}\) \(\def\itMu{\unicode{x1D6ED}}\) \(\def\itNu{\unicode{x1D6EE}}\) \(\def\itXi{\unicode{x1D6EF}}\) \(\def\itOmicron{\unicode{x1D6F0}}\) \(\def\itPi{\unicode{x1D6F1}}\) \(\def\itRho{\unicode{x1D6F2}}\) \(\def\itSigma{\unicode{x1D6F4}}\) \(\def\itTau{\unicode{x1D6F5}}\) \(\def\itUpsilon{\unicode{x1D6F6}}\) \(\def\itPhi{\unicode{x1D6F7}}\) \(\def\itChi{\unicode{x1D6F8}}\) \(\def\itPsi{\unicode{x1D6F9}}\) \(\def\itOmega{\unicode{x1D6FA}}\) \(\def\upalpha{\unicode{x03B1}}\) \(\def\upbeta{\unicode{x03B2}}\) \(\def\upvarbeta{\unicode{x03D0}}\) \(\def\upgamma{\unicode{x03B3}}\) \(\def\updigamma{\unicode{x03DD}}\) \(\def\updelta{\unicode{x03B4}}\) \(\def\upepsilon{\unicode{x03F5}}\) \(\def\upvarepsilon{\unicode{x03B5}}\) \(\def\upzeta{\unicode{x03B6}}\) \(\def\upeta{\unicode{x03B7}}\) \(\def\uptheta{\unicode{x03B8}}\) \(\def\upvartheta{\unicode{x03D1}}\) \(\def\upiota{\unicode{x03B9}}\) \(\def\upkappa{\unicode{x03BA}}\) \(\def\upvarkappa{\unicode{x03F0}}\) \(\def\uplambda{\unicode{x03BB}}\) \(\def\upmu{\unicode{x03BC}}\) \(\def\upnu{\unicode{x03BD}}\) \(\def\upxi{\unicode{x03BE}}\) \(\def\upomicron{\unicode{x03BF}}\) \(\def\uppi{\unicode{x03C0}}\) \(\def\upvarpi{\unicode{x03D6}}\) \(\def\uprho{\unicode{x03C1}}\) \(\def\upvarrho{\unicode{x03F1}}\) \(\def\upsigma{\unicode{x03C3}}\) \(\def\upvarsigma{\unicode{x03C2}}\) \(\def\uptau{\unicode{x03C4}}\) \(\def\upupsilon{\unicode{x03C5}}\) \(\def\upphi{\unicode{x03D5}}\) \(\def\upvarphi{\unicode{x03C6}}\) \(\def\upchi{\unicode{x03C7}}\) \(\def\uppsi{\unicode{x03C8}}\) \(\def\upomega{\unicode{x03C9}}\) \(\def\italpha{\unicode{x1D6FC}}\) \(\def\itbeta{\unicode{x1D6FD}}\) \(\def\itvarbeta{\unicode{x03D0}}\) \(\def\itgamma{\unicode{x1D6FE}}\) \(\def\itdigamma{\mathit{\unicode{x03DD}}}\) \(\def\itdelta{\unicode{x1D6FF}}\) \(\def\itepsilon{\unicode{x1D716}}\) \(\def\itvarepsilon{\unicode{x1D700}}\) \(\def\itzeta{\unicode{x1D701}}\) \(\def\iteta{\unicode{x1D702}}\) \(\def\ittheta{\unicode{x1D703}}\) \(\def\itvartheta{\unicode{x1D717}}\) \(\def\itiota{\unicode{x1D704}}\) \(\def\itkappa{\unicode{x1D705}}\) \(\def\itvarkappa{\unicode{x1D718}}\) \(\def\itlambda{\unicode{x1D706}}\) \(\def\itmu{\unicode{x1D707}}\) \(\def\itnu{\unicode{x1D708}}\) \(\def\itxi{\unicode{x1D709}}\) \(\def\itomicron{\unicode{x1D70A}}\) \(\def\itpi{\unicode{x1D70B}}\) \(\def\itvarpi{\unicode{x1D71B}}\) \(\def\itrho{\unicode{x1D70C}}\) \(\def\itvarrho{\unicode{x1D71A}}\) \(\def\itsigma{\unicode{x1D70E}}\) \(\def\itvarsigma{\unicode{x1D70D}}\) \(\def\ittau{\unicode{x1D70F}}\) \(\def\itupsilon{\unicode{x1D710}}\) \(\def\itphi{\unicode{x1D719}}\) \(\def\itvarphi{\unicode{x1D711}}\) \(\def\itchi{\unicode{x1D712}}\) \(\def\itpsi{\unicode{x1D713}}\) \(\def\itomega{\unicode{x1D714}}\) \(\let \lparen (\) \(\let \rparen )\) \(\newcommand {\cuberoot }[1]{\,{}^3\!\!\sqrt {#1}}\,\) \(\newcommand {\fourthroot }[1]{\,{}^4\!\!\sqrt {#1}}\,\) \(\newcommand {\longdivision }[1]{\mathord {\unicode {x027CC}#1}}\) \(\newcommand {\mathcomma }{,}\) \(\newcommand {\mathcolon }{:}\) \(\newcommand {\mathsemicolon }{;}\) \(\newcommand {\overbracket }[1]{\mathinner {\overline {\ulcorner {#1}\urcorner }}}\) \(\newcommand {\underbracket }[1]{\mathinner {\underline {\llcorner {#1}\lrcorner }}}\) \(\newcommand {\overbar }[1]{\mathord {#1\unicode {x00305}}}\) \(\newcommand {\ovhook }[1]{\mathord {#1\unicode {x00309}}}\) \(\newcommand {\ocirc }[1]{\mathord {#1\unicode {x0030A}}}\) \(\newcommand {\candra }[1]{\mathord {#1\unicode {x00310}}}\) \(\newcommand {\oturnedcomma }[1]{\mathord {#1\unicode {x00312}}}\) \(\newcommand {\ocommatopright }[1]{\mathord {#1\unicode {x00315}}}\) \(\newcommand {\droang }[1]{\mathord {#1\unicode {x0031A}}}\) \(\newcommand {\leftharpoonaccent }[1]{\mathord {#1\unicode {x020D0}}}\) \(\newcommand {\rightharpoonaccent }[1]{\mathord {#1\unicode {x020D1}}}\) \(\newcommand {\vertoverlay }[1]{\mathord {#1\unicode {x020D2}}}\) \(\newcommand {\leftarrowaccent }[1]{\mathord {#1\unicode {x020D0}}}\) \(\newcommand {\annuity }[1]{\mathord {#1\unicode {x020E7}}}\) \(\newcommand {\widebridgeabove }[1]{\mathord {#1\unicode {x020E9}}}\) \(\newcommand {\asteraccent }[1]{\mathord {#1\unicode {x020F0}}}\) \(\newcommand {\threeunderdot }[1]{\mathord {#1\unicode {x020E8}}}\) \(\newcommand {\Bbbsum }{\mathop {\unicode {x2140}}\limits }\) \(\newcommand {\oiint }{\mathop {\unicode {x222F}}\limits }\) \(\newcommand {\oiiint }{\mathop {\unicode {x2230}}\limits }\) \(\newcommand {\intclockwise }{\mathop {\unicode {x2231}}\limits }\) \(\newcommand {\ointclockwise }{\mathop {\unicode {x2232}}\limits }\) \(\newcommand {\ointctrclockwise }{\mathop {\unicode {x2233}}\limits }\) \(\newcommand {\varointclockwise }{\mathop {\unicode {x2232}}\limits }\) \(\newcommand {\leftouterjoin }{\mathop {\unicode {x27D5}}\limits }\) \(\newcommand {\rightouterjoin }{\mathop {\unicode {x27D6}}\limits }\) \(\newcommand {\fullouterjoin }{\mathop {\unicode {x27D7}}\limits }\) \(\newcommand {\bigbot }{\mathop {\unicode {x27D8}}\limits }\) \(\newcommand {\bigtop }{\mathop {\unicode {x27D9}}\limits }\) \(\newcommand {\xsol }{\mathop {\unicode {x29F8}}\limits }\) \(\newcommand {\xbsol }{\mathop {\unicode {x29F9}}\limits }\) \(\newcommand {\bigcupdot }{\mathop {\unicode {x2A03}}\limits }\) \(\newcommand {\bigsqcap }{\mathop {\unicode {x2A05}}\limits }\) \(\newcommand {\conjquant }{\mathop {\unicode {x2A07}}\limits }\) \(\newcommand {\disjquant }{\mathop {\unicode {x2A08}}\limits }\) \(\newcommand {\bigtimes }{\mathop {\unicode {x2A09}}\limits }\) \(\newcommand {\modtwosum }{\mathop {\unicode {x2A0A}}\limits }\) \(\newcommand {\sumint }{\mathop {\unicode {x2A0B}}\limits }\) \(\newcommand {\intbar }{\mathop {\unicode {x2A0D}}\limits }\) \(\newcommand {\intBar }{\mathop {\unicode {x2A0E}}\limits }\) \(\newcommand {\fint }{\mathop {\unicode {x2A0F}}\limits }\) \(\newcommand {\cirfnint }{\mathop {\unicode {x2A10}}\limits }\) \(\newcommand {\awint }{\mathop {\unicode {x2A11}}\limits }\) \(\newcommand {\rppolint }{\mathop {\unicode {x2A12}}\limits }\) \(\newcommand {\scpolint }{\mathop {\unicode {x2A13}}\limits }\) \(\newcommand {\npolint }{\mathop {\unicode {x2A14}}\limits }\) \(\newcommand {\pointint }{\mathop {\unicode {x2A15}}\limits }\) \(\newcommand {\sqint }{\mathop {\unicode {x2A16}}\limits }\) \(\newcommand {\intlarhk }{\mathop {\unicode {x2A17}}\limits }\) \(\newcommand {\intx }{\mathop {\unicode {x2A18}}\limits }\) \(\newcommand {\intcap }{\mathop {\unicode {x2A19}}\limits }\) \(\newcommand {\intcup }{\mathop {\unicode {x2A1A}}\limits }\) \(\newcommand {\upint }{\mathop {\unicode {x2A1B}}\limits }\) \(\newcommand {\lowint }{\mathop {\unicode {x2A1C}}\limits }\) \(\newcommand {\bigtriangleleft }{\mathop {\unicode {x2A1E}}\limits }\) \(\newcommand {\zcmp }{\mathop {\unicode {x2A1F}}\limits }\) \(\newcommand {\zpipe }{\mathop {\unicode {x2A20}}\limits }\) \(\newcommand {\zproject }{\mathop {\unicode {x2A21}}\limits }\) \(\newcommand {\biginterleave }{\mathop {\unicode {x2AFC}}\limits }\) \(\newcommand {\bigtalloblong }{\mathop {\unicode {x2AFF}}\limits }\) \(\newcommand {\arabicmaj }{\mathop {\unicode {x1EEF0}}\limits }\) \(\newcommand {\arabichad }{\mathop {\unicode {x1EEF1}}\limits }\)

Appendix B Java Distilled

Java is a statically typed, object-oriented programming language that shares many features with popular languages such as C++, C#, or Swift. If you know any of these languages, you won’t find it hard to follow the examples in this book. Nevertheless, a few language features and programming techniques work differently in Java or use an unfamiliar syntax. The goal of this appendix is to summarize these features.

B.1 Classes and Packages

Classes are the main abstraction in Java for organizing code and storing data. Even the simplest programs, such as the canonical “Hello World” program, require that we define a class that contains a method called main(). This method must be declared exactly as shown in the following listing:

package hello;

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello World!");
    }
}

The main() method contains the program’s code, which in this example simply calls another method called println() that prints the string "Hello World!" to the screen. If we want to call a method that is not defined inside the current class, we must specify its exact location. Here, the prefix System.out indicates that println() is defined in an object called out that is defined in a class called System.

Java classes and interfaces are organized in packages. In the example above, the HelloWorld class is placed in the hello package. By default, only names defined in the same package are visible when defining a new class. For example, assume we define a new class Greetings, which defines constants for printing “Hello World” in different languages:

package greetings;

public class Greetings {
    public static String ENGLISH = "Hello World!";
    public static String GERMAN = "Hallo Welt!";
}

Because this class is contained in a separate package greetings, it must first be imported before it can be accessed by the code in our original package hello:

package hello;

import greetings.Greetings;

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println(Greetings.ENGLISH);
    }
}

The only package that doesn’t need to be imported explicitly is java.lang, which defines classes and interfaces that are provided by the Java language and are used in almost every program. For example, in the HelloWorld class above, we were able to use the String and System classes from java.lang without first importing them. Among the many other classes defined in java.lang, the following are especially worth knowing:

  • Byte, Integer, Float, and Double provide methods for working with the built-in number types byte, int, float, and double.

  • Object is the base class of every other class in Java and defines methods that are provided by every object.

  • Math contains mathematical functions such as sqrt() and sin() and the constants PI and E.

Two special forms of import statements are worth mentioning. First, it’s possible to import every public class and interface defined in a package by using an asterisk in place of the type name:

import java.util.*;

This can be used instead of a long sequence of individual import statements such as

import java.util.List;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
...

The other special form of import statement is used to import static members from other classes. For example, Java defines standard math functions and constants as static members inside a class called Math, so every access to those members must usually be prefixed with Math.:

double y = Math.sin(Math.PI / 2);

This can be shortened by importing the two static members sin and PI at the beginning of the file:

import static java.lang.Math.sin;
import static java.lang.Math.PI;

From then on you can simply write

double y = sin(PI / 2);

It is also possible to use the asterisk syntax to import all static members defined in a class:

import static java.lang.Math.*;

To keep the code examples short, we usually omit package and import statements from code listings in this book.

By default, fields and methods are only visible to classes defined in the same package, but you can use access modifiers to change their visibility:

  • Members declared as private are only visible inside the current class.

  • Members declared as protected are only visible inside the current class and all classes derived from it.

  • Members declared as public are visible everywhere and can be used by any class defined in any package.

In practice, private and public are the most common access modifiers: private is used for things that are considered “implementation details” and public for things that are meant to be used by other code.