超初心者向け勉強会 Lesson1-2

ܕʹ͍ͭͯ NPCJMF੉ࢁ

໨త w ܕͷछྨʹֶ͍ͭͯश w ࢖͍ํΛֶश w ͦΕͧΕͷܕͰ࣮ݧΛͯ͠ཧղΛਂΊΔ

ϦϙδτϦ w 4XJGU,JOEFSHBSUFO4XJGU,JOEFSHBSUFO -FTTPO-FTTPO@

ܕͱ͸ w σʔλͷछྨΛදͨ͢Ίͷ৘ใ w σʔλͷѻ͍ΛܾΊ͍ͯΔ w ͪͳΈʹ4XJGU͸੩తݴޠͳͷͰɺܕͷෆҰக͕͋ΔͱίϯύΠϧ࣌ʹΤ ϥʔ͕ग़Δ ˞ίϯύΠϧ࣌ʹܕ͕ܾఆ͢Δͷ͕੩తݴޠɺ࣮ߦ࣌͸ಈతݴޠ

ܕͷछྨ ϓϩηοα σʔλ ྫ 4USJOH จࣈྻ lε΢Οϑτz *OU ੔਺
'MPBU ුಈখ਺఺਺ %PVCMF #PPM ਅِ஋ USVF GBMTF

Ͳ͜ʹ෇͚Δʁ var str: String = "ε΢Οϑτ" func test() -> Int
{ɾɾɾ} ओʹม਺΍ؔ਺ͷ໭Γ஋ʹ෇͚Δɻ

ܕͷෆҰக let test1: String = 1 var test2: String =
"2" test2 = 22 func test3() -> Bool { return 3 }

ͭ·Γ w ࣗ෼͕ҙਤͨ͠Α͏ʹ஋ʹҙຯΛ࣋ͨͤΔ w ᐆດʹͳΒͳ͍ w ܕΛ͚ͭΔ͜ͱ͕ɺϓϩάϥϜͷઃܭʹͭͳ͕Δؾ͕͢Δ w ࣗ෼͕ؒҧͬͨҙຯΛ࣋ͨͤΔͱϓϩάϥϜ΋ؒҧ͑Δ

ݸਓతʹؾʹͳΔ͜ͱΛ ࢼͯ͠ΈΔ

4USJOHʹ͍ͭͯ

4USJOHʹ͍ͭͯ w 4XJGUͷ4USJOH͸ɺ6OJDPEFʹ४ڌͨ͠ํ๏ͰςΩετΛѻ͏͜ͱ͕Ͱ͖ Δ w 6OJDPEFͱ͸จࣈίʔυͷࠃࡍతͳඪ४ن֨ͷҰͭʢූ߸Խจࣈू߹ʣ w จࣈʹ਺஋ΛׂΓ౰ͯΒΕ͍ͯͯɺͦͷ਺஋ΛίʔυϙΠϯτͱ͍͏ w Τϯίʔυํ๏ɿ65'
65' 65'ʢจࣈූ߸Խํࣜʣ w Ͱ͸ɺଞͷछྨͰΤϯίʔυ͢Δͱʁ ࢀߟIUUQTTXJGUQSPHSBNNJOHMBOHVBHFKQHJUCPPLJPUIFTXJGUQSPHSBNNJOHMBOHVBHFKQMBOHVBHFHVJEFTUSJOHTBOEDIBSBDUFST

4IJGU+*4Ͱ΍ͬͯΈͨ func showGarbledText() { let text = "͜Μʹͪ͸" let data
= text.data(using: .utf8)! // UTF-8Λ࢖ͬͯΤϯίʔυ // Shift JISΛ࢖ͬͯUnicodeʹม׵ͨ͠จࣈྻ if let broken = String(data: data, encoding: .shiftJIS) { print("Shift JISͰΤϯίʔυͨ͠จࣈྻ: \(broken)") } } ίϯιʔϧʹදࣔ͞ΕΔ݁Ռ Shift JISͰΤϯίʔυͨ͠จࣈྻ: ៰ಽ͂៰ő៰Ň៰ŕ

ͪͳΈʹ ࢦఆ͞ΕͨΤϯίʔσΟϯάΛ࢖༻ͯ͠ɺ༩͑ΒΕͨσʔλΛ6OJDPEFจࣈʹม׵͢Δ͜ͱͰॳظԽ͞ΕͨจࣈྻΛฦ͠·͢ɻ υΩϡϝϯτIUUQTEFWFMPQFSBQQMFDPNEPDVNFOUBUJPOTXJGUTUSJOHJOJU EBUBFODPEJOH

*OUʹ͍ͭͯ

*OUʹ͍ͭͯ ϏοτϓϥοτϑΥʔϜͰ͸ɺ*OU͸*OUͱಉ͡αΠζͰ͋Γɺ ϏοτϓϥοτϑΥʔϜͰ͸ɺ*OU͸*OUͱಉ͡αΠζͰ͋Δɻ υΩϡϝϯτIUUQTEFWFMPQFSBQQMFDPNEPDVNFOUBUJPOTXJGUJOU

*OUʹ͍ͭͯ ϓϩηοα ࠷େ஋ ࠷খ஋ CJU CJU

ϓϩηοα͕CJUͷ৔߹ // uname -m ΛλʔϛφϧͰ࣮ߦ͢Δͱ֬ೝͰ͖Δ // ࡞ऀͷMacͷϓϩηοα͸ɺx86_64Ͱ64bitͳͷͰ let maxInt64: Int
= 9223372036854775807 let minInt64: Int = -9223372036854775808 // Φʔόʔϑϩʔ 64bit let overflowMaxInt64: Int = 9223372036854775808 let overflowMinInt64: Int = -9223372036854775809 ˡ0, /( ˣ

੉ࢁ͸ߟ͑ͨɻ ܯࠂΛආ͚Δํ๏Λɻ ͦͯͨ͠ͲΓண͍ͨΫϥογϡͤ͞Δํ๏ɻ

Ϋϥογϡͤ͞Δํ๏ func clashOverflowInt() { let maxAndMinInt = self.getMaxAndMinInt() // ͲͪΒ΋Ϋϥογϡ͢Δ
_ = maxAndMinInt.max + 1 _ = maxAndMinInt.min - 1 } private func getMaxAndMinInt() -> MaxMinIntModel { // uname -m ΛλʔϛφϧͰ࣮ߦ͢Δͱ֬ೝͰ͖Δ // ࡞ऀͷMacͷϓϩηοα͸ɺx86_64Ͱ64bitͳͷͰ let maxInt64: Int = 9223372036854775807 // ࠷େ஋ let minInt64: Int = -9223372036854775808 // ࠷খ஋ return MaxMinIntModel(max: maxInt64, min: minInt64) }

ແࣄΫϥογϡ

'MPBUͱ%PVCMFʹ͍ͭͯ

ුಈখ਺఺਺ͬͯԿʁ w ܭࢉͰޡ͕ࠩൃੜ͢Δ͜ͱΛલఏͱ͍ͯ͠Δ w ۙࣅ஋ w ݶΒΕͨϦιʔεͰ޿͍ൣғͷ਺஋Λදݱ w খ਺఺ͷҐஔΛݻఆͤͣʹදݱ͞Εͨ਺

Ͳͷ͘Β͍දݱͰ͖Δʁ ܕ Ϗοτ௕ දݱͰ͖Δ஋ͷ ൣғ ༗ޮܻ਺ 'MPBU CJU ͓Αͦͷ৐ ͷਖ਼ෛ
໿ܻ %PVCMF CJU ͓Αͦͷ ৐ͷਖ਼ෛ ໿ܻ

ුಈখ਺఺਺ͷߏ଄ ܕ ූ߸෦ ࢦ਺෦ Ծ਺෦ ߹ܭ ʢϏοταΠζʣ 'MPBU
%PVCMF ࢀߟIUUQTXXXSLLDPNBSDIJWFT VUN@TPVSDFDIBUHQUDPN

ͷ৔߹ º খ਺ͷҐஔΛݻఆͤͣʹදݱ͢ΔͨΊʹɺ ද͠ํ͸ɺਐ਺ͷࢦ਺ͷදݱͷΑ͏ʹͳΔΒ͍͠ɻ ූ߸ Ծ਺ ࢦ਺ ࢀߟIUUQTXXXNBDOJDBDPKQCVTJOFTTTFNJDPOEVDUPSBSUJDMFTJOUFM

ූ߸෦ʹ͍ͭͯ w ਖ਼ෛΛද͍ͯ͠Δ w ਖ਼ͳΒɺෛͳΒ ࢀߟIUUQTXXXNBDOJDBDPKQCVTJOFTTTFNJDPOEVDUPSBSUJDMFTJOUFM º ූ߸

Ծ਺෦ʹ͍ͭͯ w ݩͷ਺ࣈ͔Βখ਺఺Λಈ͔ͨ͠஋ ࢀߟIUUQTXXXNBDOJDBDPKQCVTJOFTTTFNJDPOEVDUPSBSUJDMFTJOUFM º Ծ਺

ࢦ਺෦ʹ͍ͭͯ w খ਺఺Λಈ͔ͨ͠਺ ࢀߟIUUQTXXXNBDOJDBDPKQCVTJOFTTTFNJDPOEVDUPSBSUJDMFTJOUFM º ࢦ਺

͜ͷߏ੒Ͱɺਐ਺ʹͯ͠ ਖ਼ؾԽΛ΍ͬͯΈΔɻ ʢ'MPBUʣ

Ծ਺෦ͷද͠ํ Ծ਺෦͸ɺ੔਺෦෼ͱগ਺෦෼Λ߹Θͤͨ਺ʹͳΓ·͢ɻ ੔਺෦෼ͱগ਺෦෼Λ෼཭ Ϗοτʹม׵ ࢀߟIUUQTXXXNBDOJDBDPKQCVTJOFTTTFNJDPOEVDUPSBSUJDMFTJOUFM

Ϗοτʹม׵͢Δํ๏ ϏοτͱʢCJUʣ͸ɺίϯϐϡʔλ͕ѻ͏৘ใྔͷ࠷খ୯ҐͰɺ ਐ਺ͷܻΛࢦ͢ɻ ɹ༨Γ ɹ༨Γ ɹ༨Γ ɹ༨Γ ɹ੔਺෦෼
ɹ੔਺෦෼ ঎͕ʹͳΔ·ͰͰׂΔ ༨Γ͕ϏοτͱͳΔɻ গ਺෦෼͕ʹͳΔ·ͰΛֻ͚Δ ੔਺෦෼͕ϏοτͱͳΔɻ

Ծ਺෦ͷද͠ํ ߹ΘͤΔ খ਺఺ͷҐஔΛͭಈ͔͢ ࠷ॳͷʮʯ͸আ͘ ࢀߟIUUQTXXXNBDOJDBDPKQCVTJOFTTTFNJDPOEVDUPSBSUJDMFTJOUFM

Ծ਺෦ͷද͠ํ ߹Θͤͨ஋Λɺ੔਺෦෼͕ͰҰܻʹͳΔΑ͏ʹখ਺఺ΛҠಈͤ͞Δɻ *&&&ʹΑͬͯԾ਺͸ɺʮ Ծ਺ʯͱఆٛ͞Ε͍ͯΔͨΊΒ͍͠ɻ ͦͷͨΊɺ࠷ॳͷΛআ͍ͨʜ͕Ծ਺෦ͱͳΔɻ ࢒Γͷܻʹ͸͕ೖΔɻ ࢀߟIUUQTXXXNBDOJDBDPKQCVTJOFTTTFNJDPOEVDUPSBSUJDMFTJOUFM ࢀߟIUUQTXXXMPSSJDDPNKQ"SUJDMFT fl PXNFUFSUFDIOPMPHZ
fl PXNFUFSUFDIOPMPHZ fl PBUJOHQPJOU ʜ Ծ਺෦ ࢦ਺෦ ූ߸෦

ࢦ਺෦ͷٻΊํ Ծ਺෦ΛٻΊΔͱ͖ʹಈ͔ͨ͠ͷ͕ɺܻͳͷͰࢦ਺෦͸ʹͳΔɻ ·ͨɺ*&&&ʹΑͬͯఆٛ͞Ε͍ͯΔόΠΞε஋ΛՃࢉ͢Δɻ όΠΞε஋ ࢀߟIUUQTXXXNBDOJDBDPKQCVTJOFTTTFNJDPOEVDUPSBSUJDMFTJOUFM

׬ྃ ʜ Ծ਺෦ ࢦ਺෦ ූ߸෦ ࢀߟIUUQTXXXNBDOJDBDPKQCVTJOFTTTFNJDPOEVDUPSBSUJDMFTJOUFM

ͭ·Γ w ݶΒΕͨϦιʔεͷதͰදݱ͍ͯ͠ΔͨΊۙࣅ஋ʹͳΔ w ൣғ֎͸ؙΊࠐ·Ε͍ͯΔΒ͍͠ w 'MPBUͱ%PVCMFͰɺදݱͰ͖Δൣғ͕ҟͳΔͷͰਫ਼౓ʹ͕ࠩ͋Δ

Ͳͷ͘Β͍͕ࠩ͋Δ͔ ൺֱͯ͠Έͨ

ൺֱ private let iterations = 10_000_000 func calcFloatValue() { var
result: Float = 0.0 let start = Date() for _ in 0..<self.iterations { result += 1.0 / 3.0 } let end = Date() let elapsed = end.timeIntervalSince(start) // ඵ print("FloatܕͰܭࢉͨ݁͠Ռ:\(result)") print("\(elapsed)ඵ͔͔Γ·ͨ͠ɻ") } func calcDoubleValue() { var result: Double = 0.0 let start = Date() for _ in 0..<self.iterations { result += 1.0 / 3.0 } let end = Date() let elapsed = end.timeIntervalSince(start) print("DoubleܕͰܭࢉͨ݁͠Ռ:\(result)") print("\(elapsed)ඵ͔͔Γ·ͨ͠ɻ") } ίϯιʔϧʹදࣔ͞ΕΔ݁Ռ FloatܕͰܭࢉͨ݁͠Ռ:3090156.2 0.9137569665908813ඵ͔͔Γ·ͨ͠ɻ DoubleܕͰܭࢉͨ݁͠Ռ:3333333.3337136623 0.9393709897994995ඵ͔͔Γ·ͨ͠ɻ

#PPMʹ͍ͭͯ

#PPMͷத਎Ͳ͏ͳͬͯΔͷʁ ਓͷ໨ͰݟͨΒUSVFͱGBMTF ͚ͩͲɻ

ϝϞϦ্ͷ஋Λ֬ೝͯ͠Έͨ func showBoolBytes() { // σʔλͷόοϑΝ಺ͷੜͷόΠτʹΞΫηε withUnsafeBytes(of: true) { (bytes:
UnsafeRawBufferPointer) in print("trueͷϝϞϦ্ͷ਺஋:") bytes.forEach { print($0) } } withUnsafeBytes(of: false) { (bytes: UnsafeRawBufferPointer) in print("falseͷϝϞϦ্ͷ਺஋:") bytes.forEach { print($0) } } } ίϯιʔϧʹදࣔ͞ΕΔ݁Ռ trueͷϝϞϦ্ͷ਺஋: 1 falseͷϝϞϦ্ͷ਺஋: 0 ࢀߟIUUQTEFWFMPQFSBQQMFDPNEPDVNFOUBUJPOGPVOEBUJPOEBUBXJUIVOTBGFCZUFT @

·ͱΊ w ܕ͸ɺσʔλͷѻ͍ΛܾΊ͍ͯΔ w 4XJGUͷ4USJOHܕ͸ɺ6OJDPEFʹ४ڌ͍ͯ͠Δ w *OU͸ɺϓϩηοαʹΑͬͯ࠷େ஋ͱ࠷খ஋͕͋Δ w ුಈখ਺఺਺͸ɺۙࣅ஋Ͱ͋Γ'MPBUͱ%PVCMFͰਫ਼౓͕ҟͳΔ w
USVFͱGBMTF͸ɺͱͩͬͨ

ϦϯΫू w IUUQTTXJGUQSPHSBNNJOHMBOHVBHFKQHJUCPPLJPUIFTXJGUQSPHSBNNJOHMBOHVBHFKQMBOHVBHFHVJEFTUSJOHTBOE DIBSBDUFST w IUUQTEFWFMPQFSBQQMFDPNEPDVNFOUBUJPOTXJGUTUSJOHJOJU EBUBFODPEJOH w IUUQTEFWFMPQFSBQQMFDPNEPDVNFOUBUJPOTXJGUJOU
w IUUQTXXXSLLDPNBSDIJWFT VUN@TPVSDFDIBUHQUDPN w IUUQTXXXNBDOJDBDPKQCVTJOFTTTFNJDPOEVDUPSBSUJDMFTJOUFM w IUUQTXXXMPSSJDDPNKQ"SUJDMFT fl PXNFUFSUFDIOPMPHZ fl PXNFUFSUFDIOPMPHZ fl PBUJOHQPJOU w IUUQTEFWFMPQFSBQQMFDPNEPDVNFOUBUJPOGPVOEBUJPOEBUBXJUIVOTBGFCZUFT @

超初心者向け勉強会 Lesson1-2

超初心者向け勉強会 Lesson1-2

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