Isakhiwo Uhlelo e Pascal: Ukuhlela Wabasaqalayo

I okungabizi kakhulu ulimi lokwakha Wabasaqalayo kuyinto Pascal. Lokhu kungenxa okungenani yokuthi wafundiswa ezikoleni zamabanga aphakeme, kanye freshman esikoleni esiphakeme. Isetshenziselwa njengoba base sokuthuthukiswa nezinye izilimi eziningi. Nokho, njengoba nje nengaphakathi sokuthuthukiswa ukusetshenziswa kwalo engenangqondo manje njengoba imishini yezobuchwepheshe it is gone phambili.

Manje kukhona imali eningi ukuthi ukugcina le-syntax. Ziyahlukahluka kuye kuphela medium izinhlelo ulimi ezifana Pascal. Isakhiwo Uhlelo atawutadishelwa esihlokweni. Njengomthetho, ujwayele izinhlelo iqala uhlelo "Sawubona, izwe!".

umlando ulimi

Pascal budalulwa ngo-1970 ngenxa, Isimanga siwukuthi, Niklaus Wirth. igama lolimi olunikeziwe behlonipha Blaise Pascal - indoda mkhulu odabuka eFrance. Lokhu ulungisiswa yokuthi usosayensi idale umshini wokuqala emhlabeni ukuthi wakwazi ukuze ungeze futhi ukhiphe izinombolo.

ukuthuthukiswa Ulimi kwenziwa kusukela ngo-1968 kuya 1969. Lapho kukhulunywa ngaye okokuqala uvele 1970. umdali, ethula "ingane" yakhe, igxile isitayela izinhlelo, kanye nedatha okufakwayo Pascal. isakhiwo iqiniso lokuthi loluhlelo luye futhi lakhiwe ngokuhlanganyela Wirth. It has a-syntax elula engasho lutho. Direct "ozalweni" Pascal siwulimi "Modula-2." Umthuthukisi Its futhi isibe Wirth.

imithetho lolimi

Kufanele kuqashelwe ukuthi akunzima kangako kule isakhiwo Uhlelo limi. Umbhali Pascal wabeka ukusetshenziswa amaphuzu ayinhloko amathathu kuphela - isihloko, incazelo, kanye opharetha.

1. Isihloko. Lapha kumele icacise igama uhlelo, kodwa nto ayiyona ezinkulu. It is wadala kuphela uma unjiniyela oyifunayo. Ngokusho ngokwezinga elikhulu incike imvelo izinhlelo. Ngo-Turbo Pascal akudingeki it. Kodwa ngaleso Eth kuphoqelekile ukudala yezinhlamvu. Sebenzisa avunyelwe nezinhlamvu zamagama nezinombolo kuphela futhi kugcizelelani "_".
2. Incazelo. Lesi sigaba ubala zonke eziguquguqukayo etholakalayo (afanayo), amalebula, nokunye. D.
3. Operator. e Pascal Uhlelo isakhiwo ihlanganisa incazelo opharetha kubakaki ZIQALA-END.

Kungakanani bayoba nasendleleni efanayo, akunandaba. Into esemqoka - ngemuva kokuphela ithimba ngalinye ukubeka uhlamvu ekhethekile --semicolon. Ngaphezu kwalokho, ulimi icala bangakhathaleli muntu: akukho umahluko phakathi opharetha Var, futhi var var.

Syntax futhi Isemanthikhi

Central nomsebenzi zamagama Udlala imvelo izinhlelo. Khumbula ukuthi liqukethe:

• elifunyenwe, kokubili usonhlamvukazi kanye ezincane;
• isikhala;
• kugcizelela;
• Arabic amadijithi uhlobo;
• izimpawu zezibalo;
• limiters (ohlwini yabo yokungena, ukhefana, njll ...);
• specifiers;
• amazwi asizayo (opharetha).

Sakhiwo kohlelo Turbo Pascal akuhlukile isakhiwo PascalABC. Umehluko kuyo e idatha yangaphandle, akukho okunye. Ukuze babonise ukuthi kwakusazoba igama variable, kanye nezinye izinhlobo, kubalulekile ukukhumbula ukuthi igama akufanele ngenombolo, uhlamvu kugcizelelani kungaba yisiphi isimo, kodwa kusukela izimpawu zamagama abavunyelwe ukusebenzisa kuphela izinhlamvu izinhlamvu zesiLatini.

Amazwana ku imigqa Kuphakathi besokunxele noma round lwenkanyezi (* .. *).

nedatha

Isakhiwo kohlelo Pascal, futhi kuhlanganisa ukucabangela izinto, ezifana izinhlobo idatha. Bona bangabezwe; ezintathu izinhlobo:

1. Izimiso eziphusile (kweqiniso nokwamanga);
2. yezinombolo (izinombolo Arabhu);
3. uhlamvu (ukusetshenziswa a, b, c no t. d.).

Ngesikhathi esifanayo, uhlobo lwesibili uhlukaniswe sub-zinhlobo: inamba kanye langempela. Bona zivumelana opharetha ezithile: Inombolo ephelele futhi Real ngokulandelana. Uhlamvu futhi ihlukaniswe yaba izinhlamvu olulodwa futhi izintambo. Lokhu kusho ukusebenzisa izinhlobo zedatha ezifana (esimweni sokuqala), inombolo 1, uhlamvu A noma A, kanye (wesibili) wonke umusho noma inkulumo. In the hlelo, alotshwe ngaphansi amagama Char futhi Spring.

Amanani futhi babe ngezigaba zabo. Basuke ihlukaniswe njalo futhi variable. Umehluko phakathi yona ibaluleke. I yokuqala isikisela ukubaluleka izinhlamvu okuyinto musa ukushintsha phakathi Uhlelo kuqalisa. A variable inikezwa ukubaluleka ngokuhamba usebenzisa uhlamvu ekhethekile - le ikholoni.

Amazwana

Ukuze kuzuzwe ukuqonda ngokugcwele uhlelo nazo zonke izinqubo zawo, umsebenzi amazwana. Ababona, njengoba kuye kwashiwo ngenhla, ezibekwe kubakaki abacaphuni. Lokhu kubalulekile ikakhulukazi uma ngabe umusha ku ukubuka ikhodi. Ngoba, usebenzisa le ndlela, ungakwazi ukuthola kalula iphutha uhlelo ngomumo eyenziwe, ngokusekelwe kulokho okulotshwe amazwana. Ngaphezu kwalokho, bazokusiza umthuthukisi ne isikhathi ayiqonde ikhodi isofthiwe.

Sakhiwo kohlelo Pascal ngemfanelo ivumela amazwana ku isakhiwo idatha kuchaziwe block yesibili. Kube Udinga ukufaka umbhalo, elizoquketha injongo opharetha ngamunye nendlela isetshenziswa esikhathini esizayo.

Newbie ukusiza uzulazule kubakaki ZIQALA-END amazwana elibazungezile. Ikakhulukazi kuyoba usizo endaweni imijikelezo Uhlelo ngamakhasimende. Ngakho-ke kuyoba lula ukuqonda ukuthi yini block of izitatimende iphelile.

Amazwana awakwazi ukufunda izinhlelo imvelo, ukuze bakwazi ukubamba iyiphi inombolo isikhathi ayigcini e izinombolo ngokulandelana kwezinhlamvu zamagama.

izimpawu zokuloba

Isakhiwo Uhlelo e Pascal has zokuloba yayo, kodwa-ke, akusona isimanga. Indlela esetshenziswa kakhulu isibonakaliso isemikholoni. It ibekwe emva ngamunye incazelo block Ilebula, Uhlobo, const, Var futhi t. E., Kodwa uphawu ayidingeki emva amazwi uzimisele kakhulu. ayifakiwe emva Qala; ngemva END ukubeka kuphela uma uhlelo is hhayi kuqeda okwamanje. Esikhathini ikhodi, lapho kukhona imijikelezo futhi, ngokufanelekile, asetshenziswa, kanye Else Bese, isemikholoni ayidingeki ngemva kwala mazwi.

Ekupheleni kohlelo ngemuva UKUPHELA Kuzomele ufake iphuzu, kungenjalo imvelo izinhlelo akaqondi ukuthi ikhodi isiqedile.

Idatha input bese okukhipha

Isakhiwo Uhlelo e Pascal ikuvumela ukungena idatha ngezindlela ezintathu ezahlukene. Phakathi kwabo:

• Ngosizo Readln opharetha, Funda.
• With ukusetshenziswa uphawu isabelo - ikholoni.
• Njalo. Esimweni esinjalo, imininingwane efakwayo wenziwa ku var ipharamitha.

Isiphetho etholwe Imininingwane zingenziwa ngokusebenzisa kweqembu Bhala Writeln opharetha. Kwezinye izimo kungase kube ulahlekile, kodwa nje kusho ukuthi usevele ezakhelwe inqubo ukukhiqizwa.