これからのJavaのとっかかりを掴む

2015-04-08 Java Day Tokyo 2015
2015-10-05 秋の関ジャバ祭り https://kanjava.connpass.com/event/14086/

Slideshareに上げているものと同じです。

Transcript

1. ͜Ε͔Βͷ+BWBͷ
   ͱ͔͔ͬΓΛ௫Ή
   ळͷؔδϟόࡇΓ
   LBOKBWB
   !JSPG
   +BWB%BZ5PLZP
   KEU
   !JSPG
   

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2. +BWBΤϯδχΞཆ੒ಡຊ

   +BWBೖ໳
   ։ൃݱ৔ʹ఻͍͑ͨͷ͜ͱ

   ಓ۩ʹؔ͢ΔΑ͠ͳ͠͝ͱ
   ؔ੢+BWBΤϯδχΞͷձ
   @irof
   IPHFۦಈ
   ϨϏϡΞʔ
   

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3. ͜Ε͔Β͢Δ࿩
   ͜Ε·Ͱͷ+BWBΛৼΓฦͬͯ
   ͍·Ͳ͖ͷ+BWBͷ଍৔ݻΊ
   ͜Ε͔Βͷ+BWBͷͱ͔͔ͬΓ
   ˞ϓϩάϥϚ޲͚
   

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4. ͠ͳ͍࿩
   +BWBҎ߱ͷ۩ମతͳ࿩
   

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5. ͜Ε·Ͱͷ+BWBΛ
   ৼΓฦͬͯ
   ͜Ε·Ͱͷ+BWB+BWB4&͋ͨΓ
   

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6. ʮ͜Ε·Ͱʯ
   ʹؚ·ΕΔ΋ͷ
   δΣωϦΫε
   FOVN
   ֦ுGPS
   Ξϊςʔγϣϯ
   $PODVSSFODZ6UJMJUJFT
   

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7. ͜Ε·Ͱͷ+BWBΛΠϝʔδͰ࿩͠·͢
   ˞ݸਓͷײ૝Ͱ͢
   

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8. +BWBݴޠ
   

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9. +BWBݴޠ
   ݎ͍ۤ͠
   ੩తܕ෇͚ΦϒδΣΫτࢦ޲ݴޠ
   ৑௕ͳߏจ
   ྼԽ999ݴޠ
   อकత
   ݹष͍
   ख͕ؒଟ͍
   ਐԽ͕஗͍
   ॲཧ͕஗͍
   ىಈ͕஗͍
   Α͘࢖ΘΕ͍ͯΔ
   ϙετ$0#0-
   Ϋϥεϕʔε
   

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10. +BWB؀ڥ
    

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11. +BWB؀ڥ
    ࣮੷ࣄྫ͕ଟ͍
    ԯͷσόΠεͰಈ͘
    +7.
    αʔόʔ͔ΒϞόΠϧ·Ͱ
    +7.ݴޠ
    ৘ใ͕ಘ΍͍͢
    ๲େͳϥΠϒϥϦ΍
    ϑϨʔϜϫʔΫ
    ॆ࣮ͨ͠։ൃπʔϧ
    Φʔϓϯιʔε
    

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12. ͜Ε·Ͱͷ+BWBͷΠϝʔδ
    ݴޠ͸Α͘࢖ΘΕ͍ͯΔ
    ҰํͰωΨςΟϒͳҹ৅΋ڧͦ͏
    ؀ڥ͸جຊతʹϙδςΟϒͳײ͡
    

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13. Ҏ্͕z͜Ε·Ͱzͷ࿩
    

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14. +BWB͸มΘ͍ͬͯ·͢
    ʢͨͿΜʣ
    

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15. ͍·Ͳ͖ͷ+BWBͷ
    ଍৔ݻΊ
    

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16. ͍·Ͳ͖ͷ+BWBݴޠ
    ͍·Ͳ͖ͷ+BWB+BWB +BWB
    ίʔυͱͱ΋ʹ͓͞Β͍ɻ
    

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17. +BWBϐοΫΞοϓ
    +BWB4& +43
    
    1SPKFDU$PJO +43
    
    /*0 +43
    
    

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18. +431SPKFDU$PJO
    USZXJUISFTPVSDFT
    EJBNPOEPQFSBUPS
    $PJOͰ΋Α͘࢖͏΋ͷ
    

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19. USZXJUISFTPVSDFT
    Closeable resource = create();

    try {

    // resource Λ࢖͏ॲཧ...

    } finally {

    resource.close();

    }
    try (AutoCloseable resource = create()) {

    // resource Λ࢖͏ॲཧ...

    }
    

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20. EJBNPOEPQFSBUPS
    Map>> map

    = new HashMapString>>>();

    Map>> map

    = new HashMap<>();
    

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21. ଞͷ$PJOͨͪ
    όΠφϦϦςϥϧ
    ਺஋ϦςϥϧͷΞϯμʔείΞ
    4USJOHTTXJUDI
    ϚϧνΩϟον
    

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22. ଞͷ$PJOͨͪ
    όΠφϦϦςϥϧ
    ਺஋ϦςϥϧͷΞϯμʔείΞ
    4USJOHTTXJUDI
    ϚϧνΩϟον
    Ϧςϥϧ
    ͋Μ·Γ
    ॻ͔ͳ͍
    

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23. 4USJOH4XJUDI
    switch (str) {

    case "java":

    // ...

    break;

    case "groovy":

    // ...

    break;

    default:

    // ...

    }
    OVMM͜Θ͍
    CSFBLΊΜͲ͍
    JGͰॻ͘ΑΓ

    ߦ਺ଟ͍
    

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24. ϚϧνΩϟον
    try {

    this.getClass().getMethod("method").invoke(this);

    } catch (IllegalAccessException

    | NoSuchMethodException

    | InvocationTargetException e) {

    // ...

    }
    try {

    this.getClass().getMethod("method").invoke(this);

    } catch (ReflectiveOperationException e) {

    // ...

    }
    ϦϑϨΫγϣϯ͸جఈྫ֎ΫϥεͷDBUDIͰΑ͛͞
    

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25. +43/*0
    +BWBͰϑΝΠϧΛѻ͏ؾʹͳΕΔʢॏཁʣ
    

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26. /*0
    List lines = new ArrayList();

    BufferedReader br = new BufferedReader(

    new InputStreamReader(

    new FileInputStream(fileName),
    StandardCharsets.UTF_8));

    for (String line; (line = br.readLine()) != null; ) {

    lines.add(line);

    }
    List lines = Files.readAllLines(path);
    🌾DMPTFলུ
    

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27. +BWBϐοΫΞοϓ
    +BWB4& +43
    
    1SPKFDU-BNCEB +43
    
    %BUFBOE5JNF"1* +43
    
    

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28. +43
    1SPKFDU-BNCEB
    -BNCEB&YQSFTTJPO
    .FUIPE3FGFSFODF
    0QUJPOBM
    

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29. -BNCEB&YQSFTTJPO
    (String arg) -> { /* ͳΜ͔ॲཧ */ }
    arg -> /* ͳΜ͔ࣜ */
    System.out::println
    .FUIPE3FGFSFODF
    

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30. 0QUJPOBM
    MBNCEBͱͷซ༻͕جຊ
    JT1SFTFOU࢖͏ͱΠϚΠν
    OVMMΛࠜઈ΍͠ʹͯ͠΄͍͠
    Optional java = Optional.of(“java");
    

    java.ifPresent(System.out::println);
    

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31. +43
    %BUFBOE5JNF"1*
    %BUF5JNF%BUF5JNF
    -PDBM;POFE
    %BUF5JNF'PSNBUUFS
    ͳͲʜʜ
    

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32. ͋Θͤͯݟͯཉ͍͠
    

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33. ͍·Ͳ͖ͷ+BWB؀ڥ
    ϥΠϒϥϦ΍ϑϨʔϜϫʔΫ
    *%&
    ϏϧυγεςϜ
    

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34. ϥΠϒϥϦ΍
    ϑϨʔϜϫʔΫ
    ૬มΘΒͣͨ͘͞Μ͋Δ
    Ή͠Ζ૿͑ΔҰํ
    ੈ୅ަ୅΍ํ޲ੑͷมಈ͕ىͬͯͨ͜Γ
    +BWB&&΍4QSJOH#PPUͳͲͷྲྀΕ
    

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35. *%&
    &DMJQTFͷಠஃ৔͔Βબ୒΁
    &DMJQTF
    /FU#FBOT
    *OUFMMJ+*%&"
    

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36. ϏϧυγεςϜ
    "OU.BWFO͔Β(SBEMF΁ʁ
    ҰؾʹมΘΔؾ഑͸ͳͦ͞͏
    ঃʑʹมΘ͍ͬͯΔҹ৅͸͋Δ
    

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37. ͜Ε·Ͱ͍·Ͳ͖
    ݴޠ
    ݹष͞΍৑௕͞͸১ΘΕͭͭ͋Δ
    ؀ڥ
    ͜Ε·ͰΛϕʔεʹΑΓڧྗʹ
    

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38. ࣌ʹ
    l͍·Ͳ͖ͷ+BWBz
    ࢖ͬͯ·͢ʁ
    

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39. ͍·Ͳ͖ͷ+BWB
    ͳΜ͔ඍົͳײ͕͢͡ΔɻͳΜͰʁ
    ࢖͑Δਓ͕͍ͳ͍ʁ
    ಈ͔ͳ͍ʁ
    

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40. ࢖͑Δਓ͕͍ͳ͍ʁ
    ࢖ͬͯͳ͍΋ͷΛ࢖͑ΔΑ͏ʹɺͳΜͯ

    ͳΔΘ͚͕ͳ͍ɻ
    ࢖ͬͯͳ͍͔Β࢖Θͳ͍ͱ͔ݴͬͯΔͱ

    ͍ͭ·Ͱ΋มΘΒͳ͍ɻ
    

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41. ࢖͑Δਓ͕͍ͳ͍ʁ
    +BWB4& ͷ৘ใ͸े෼ग़ճͬͯΔ
    ͦͷลΛݟͯษڧ͍ͯ͠Δํʑ΋ډΔ
    ʮ࢖ͬͨ͜ͱͳ͍ਓ͕ଟ͍ʯͳΒɺ࢖͑͹͍
    ͍͚ͩͷ࿩
    ࢖ͬͨ͜ͱͷ͋Δਓ͸૿͑Δ͜ͱ͸͋ͬͯ
    ΋ݮΓ͸͠ͳ͍ͷ͔ͩΒ
    

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42. ಈ͔ͳ͍ʁ
    όʔδϣϯΞοϓͨ͠Βಈ͔ͳ͘ͳΔͱݴ͏
    ࿩͕ͪΒ΄Βͱ
    

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43. +BWBͷޓ׵ੑ
    

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44. ;ͭ͏ʹແཧͳ͜ͱ
    +%,Ͱ;ͭ͏ʹίϯύΠϧͨ͠
    DMBTTϑΝΠϧΛ+3&͸ಡΊͳ͍
    -BNCEB
    ஌ΒΜ͕ͳʜʜ
    ͱ͸͍͑ʜʜ
    +3&͞Μ
    

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45. ޙํޓ׵ੑ͸΄΅໰୊ແ͍
    +4&࣌୅ͷίʔυ͸ŠŠ
    ͍͍ͩͨ+%,ͰίϯύΠϧՄೳ
    +4&࣌୅ͷDMBTT΍KBS͸ŠŠ
    ͍͍ͩͨ+3&Ͱ࣮ߦՄೳ
    

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46. ޙํޓ׵ੑ͸΄΅໰୊ແ͍
    +4&࣌୅ͷίʔυ͸ŠŠ
    ͍͍ͩͨ+%,ͰίϯύΠϧՄೳ
    +4&࣌୅ͷDMBTT΍KBS͸ŠŠ
    ͍͍ͩͨ+3&Ͱ࣮ߦՄೳ
    

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47. ӡ͕ѱ͍ͱࣄނΔ
    ม਺໊ʹFOVNΛ࢖ͬͯͯίϯύΠϧΤϥʔ
    ΠϯλϑΣʔεʹϝιου͕૿͑ͯίϯύΠϧ
    Τϥʔ
    ࠶ίϯύΠϧͤͣಈ͔ͨ͠Β࣮ߦ࣌ྫ֎
    ϦϑϨΫγϣϯͰऔΕΔॱ൪͕มΘͬͯ༧ظ
    ͠ͳ͍ྫ֎
    ͱ͸ݴ͑͜Ε͸ӡ͕ѱ͍࿩
    

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48. +BWBࣗମ͸ͱ΋͔͘
    ϥΠϒϥϦ͸ͭΒ͍
    

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49. ରԠ͍ͯ͠ͳ͍ϥΠϒϥϦ͕͋Δ
    

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50. ରԠ͍ͯ͠ͳ͍ϥΠϒϥϦ͕͋Δ
    ର৅ϥΠϒϥϦͷΞοϓσʔτ
    

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51. ରԠ͍ͯ͠ͳ͍ϥΠϒϥϦ͕͋Δ
    ର৅ϥΠϒϥϦͷΞοϓσʔτ
    ґଘ͢ΔϥΠϒϥϦͷΞοϓσʔτ
    ґଘ͢ΔϥΠϒϥϦͷΞοϓσʔτ
    

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52. ରԠ͍ͯ͠ͳ͍ϥΠϒϥϦ͕͋Δ
    ର৅ϥΠϒϥϦͷΞοϓσʔτ
    ґଘ͢ΔϥΠϒϥϦͷΞοϓσʔτ
    ґଘ͢ΔϥΠϒϥϦͷΞοϓσʔτ
    ґଘ͢ΔϥΠϒϥϦͷΞοϓσʔτ
    ґଘ͢ΔϥΠϒϥϦͷΞοϓσʔτ
    ґଘ͢ΔϥΠϒϥϦͷΞοϓσʔτ
    ґଘ͢ΔϥΠϒϥϦͷΞοϓσʔτ
    ͭΒ͍
    

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53. +BS)FMM
    ੲ͸KBSΛखಈͰ͔͖ूΊΔ͜ͱʹΑΔ࡞ۀ஍
    ࠈΛҙຯ͍ͯͨ͠
    Ϗϧυπʔϧ͕ґଘΛࣗಈͰղܾ͢Δ͜ͱͰ
    ऴΘ͔ͬͨʹࢥ͕͑ͨ
    ࠷ۙ͸KBSؒͷґଘ͕ಊʑ८Γ͢Δ͜ͱʹΑΔ
    ແؒ஍ࠈΛҙຯͯ͠ΔΑ͏ͳؾ͕͢Δ
    

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54. ϥΠϒϥϦͱޓ׵ੑ
    Ϋϥεͷ౷ഇ߹ɺجఈΫϥε΍ΠϯλϑΣʔ
    εͷมߋʹΑΓιʔεޓ׵͸͋ͬ͞ΓଛͳΘ
    Εͯ͠·͏ʢ͜ͱ΋͋Δʣ
    ϦϑϨΫγϣϯͷಈ࡞΍ɺΫϥεϑΥʔϚο
    τͳͲɺ௨ৗͷޓ׵ੑ΄ͲڧݻʹकΒΕ͍ͯ
    ͳ͍΋ͷʹґଘ͍ͯ͠Δʢ͜ͱ΋͋Δʣ
    ڧྗͳϥΠϒϥϦ΄Ͳ܏޲͸ڧ͍ʢؾ͕͢Δʣ
    

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55. ϥΠϒϥϦͱޓ׵ੑ
    +BWBͷڧΈͷ͸ͣͷʮϥΠϒϥϦͷॆ࣮ʯ
    ޓ׵ੑΛߟ͑ΔͱωοΫʹͳΔ
    όʔδϣϯΞοϓ࣌͸ಛʹݦஶ
    ৐Γӽ͑ͳ͍ͱz͍·Ͳ͖ͷ+BWBz͕࢖͑ͳ͍
    

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56. ͱ͸͍͑
    ద੾ͳॱ൪Ͱόʔδϣϯ͍͚͋͛ͯ͹ɺҙ֎
    ͱ͢ΜͳΓ্͛ΒΕͨΓ͢Δɻ
    ϝδϟʔόʔδϣϯΞοϓز͔ͭ΍͚ͬͨͲɺ
    ϋϚΔͷ͸ʮ·͍͔ͨͭ͜ʯͱ͍͏Ұ෦Ͱ͢ɻ
    

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57. ͳΜͱ͔ͳΔ
    

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58. ੜ͖ͨ+BWBΛ࢖͍ͬͯͨ͘Ίʹ΋ɺ͍·Ͳ͖
    ͷ+BWBΛ஌ͬͯ࢖͍͖ͬͯ·͠ΐ͏ɻ
    

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59. ͜Ε͔Βͷ+BWBͷ
    ͱ͔͔ͬΓ
    

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60. ͜Ε͔Βͷ+BWB
    1SPKFDU+JHTBX
    1SPKFDU7BMIBMMB
    1SPKFDU1BOBNB
    ࠷ॳʹݴͬͨ௨Γ
    ͜ͷลͷ࿩͸͠·ͤΜ
    

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61. ͜Ε·Ͱˠ͜Ε͔Β
    Ұ൪ͷҧ͍͸ʮ+BWBࣗ਎͕੒௕͢Δʯ͜ͱ
    গ͠લʹ+BWB4&͕ग़ͯ
    ͦͷ೥ͪΐ͍ޙʹ+BWB4&͕ग़ͯ
    ͨͿΜ೥͘Β͍ޙʹ+BWB4&͕ग़Δ
    

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62. ೥લ
    
    ೥લ
    
    

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63. J2SE 5.0
    ೥લ
    
    ೥લ
    
    

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64. J2SE 5.0
    Java SE 6
    ೥લ
    
    ೥લ
    
    

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65. J2SE 5.0
    Java SE 6 Java SE 7
    ೥લ
    
    ೥લ
    
    

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66. J2SE 5.0
    Java SE 6 Java SE 7
    Java SE 8
    ೥લ
    
    ೥લ
    
    

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67. J2SE 5.0
    Java SE 6 Java SE 7
    Java SE 8
    ೥લ
    
    ೥લ
    
    ໿೥
    

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68. ̑೥ͷϒϥϯΫ
    +BWB͔ΒΛݟૹͬͨΒܖػΛࣦͬͨ
    +BWBͰ࡞ͬͨΒػձ͕དྷͳ͔ͬͨ
    ্͛ΒΕͳ͍··ಈ͚ͳ͘ͳͬͯ͠·ͬͨ
    J2SE 5.0
    Java SE 6 Java SE 7
    Java SE 8
    ໿೥
    

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69. ͱ͸ݴ͑͜Ε͔Β͸ߋ৽͞Ε͍ͯ͘ͷͰɺ

    ண͍͍͖͍ͯͨͱ͜ΖͰ͸͋Δɻ
    

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70. ߋ৽ͯ͠Έͨ࿩ͦͷ
    ࣮ߦ؀ڥ͚ͩ+BWBʹͯ͠Έͨ
    ίʔυɺίϯύΠϥ͸+BWBͷ··
    ϥΠϒϥϦ͸ߋ৽ͤͣ
    ͍͚ͨˠͳΜͷ໰୊΋ͳ͘ಈ͍͍ͯΔ
    

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71. ߋ৽ͯ͠Έͨ࿩ͦͷ
    ࣮ߦ؀ڥ͚ͩ+BWBʹͯ͠Έͨ
    ίʔυɺίϯύΠϥ͸+BWBͷ··
    ϥΠϒϥϦ͸ߋ৽ͤͣ
    ͩΊͩͬͨˠ࣮ߦ؀ڥͷόʔδϣϯ֬ೝ͠
    ͍ͯΔϥΠϒϥϦ͕͋ͬͨʜʜ
    

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72. ߋ৽ͯ͠Έͨ࿩ͦͷ
    ίϯύΠϥ͚ͩ+BWBʹͯ͠Έͨ UBSHFU
    
    ίʔυɺ࣮ߦ؀ڥ͸+BWBͷ··
    ϥΠϒϥϦ͸ߋ৽ͤͣ
    ͍͚ͨˠͳΜͷ໰୊΋ͳ͘ಈ͍͍ͯΔ
    

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73. ߋ৽ͯ͠Έͨ࿩ͦͷ
    ίϯύΠϥ࣮ߦ؀ڥͱ΋ʹ+BWBʹͯ͠Έͨ
    ίʔυ͸+BWBͷ··
    ϥΠϒϥϦ͸ߋ৽ͤͣ
    ͍͚ͨˠͳ͔ͥಈ͍ͯ͠·ͬͨ
    ͚ͲMBNCEBͭॻ͍ͨॠؒམͪͨ
    

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74. ͜Ε͔Βͷͱ͔͔ͬΓ
    +BWB͸ੜ͖ͯͯɺݩؾʹಈ͖࢝Ίͨ
    ͦΜͳ+BWBʹৼΓམͱ͞Εͳ͍ͨΊʹ
    

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75. ݴޠͷͱ͔͔ͬΓ
    -BNCEBʹ͍ͭͯ͜ΕͯΔʁ
    (SPPWZ΍4DBMBͳΜ͔Λ΍ͬͯͨਓ͸ฏવ
    ͱѻͬͯΔ
    ࠓޙͷ+BWBʹ௥ਵ͢ΔͨΊʹผͷݴޠʹ΋৮
    Ε͓ͯ͘ͱ͍͍͔΋
    

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76. ؀ڥͷͱ͔͔ͬΓ
    Ϗϧυπʔϧ͸ΑΓਐԽ͍ͯ͘͠͸ͣ
    ΋ͬͱେ͖͘ͳ؀ڥΛϏϧυͦ͠͏
    ͦͷ͏ͪ+BS)FMMΛղফͯ͘͠ΕΔ͔΋
    ݱঢ়Ͱ΋ཧղ͓͚ͯ͠͹े෼ͳ෢ثʹͳΔ
    

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77. લʹਐΉͳΒ͹
    ৽چͷ৘ใͷݟۃΊ͸೉͘͠ͳ͍ͬͯ͘
    ෆ҆ͳϥΠϒϥϦͷ૊Έ߹Θͤ΋
    ΞμϓλΛ࣮૷͢Δඞཁ΋͋Δ͔΋
    ಈ͔ͯ͠ݕূ͢Δࣗಈςετ͸·͢·͢ॏཁ
    ʹͳͬͯ͘Δͱࢥ͏
    

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78. ཹ·Δ༐ؾ
    ແཧͤͣཹ·Δબ୒ࢶ΋ߟྀʹೖΕΔ
    ݹ͍ίʔυɺݹ͍ίϯύΠϥɺ৽͍࣮͠ߦ
    ؀ڥͱ͔Ͱ΋͍͍ͩͨେৎ෉
    ҆શࡦΛͱΔͳΒ࣮ߦ؀ڥ΋αϙʔτड͚Ε
    ʢۚͰͿΜԥΕ͹ͳΜͱ͔ͳΔʣ
    &OEPG1VCMJD6QEBUFT&0-
    

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79. प೥Λܴ͑ɺ+BWB͸·͢·͢ݩؾ
    ͜Ε͔Β΋+BWBͱڞʹߦͨ͘Ίʹ

    ͓ޓ͍ʹ৘ใग़͠߹͍͖ͬͯ·ͤΜ͔ʁ
    ͝੩ௌ͋Γ͕ͱ͏͍͟͝·ͨ͠
    

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