Da'ira for: Pascal ga sabon shiga

Shirye-shirye muhimmai - hawan keke, misali, ga. Pascal. Kamar yadda da kowace kwamfuta harshe, shi ma yana dauke da irin wannan kayayyaki a cakude.

Nada cyclic aiki

A hankula aiki - don samun kwamfuta don yin wannan mataki sau da yawa. Ga kuma ajiye zane, kyale tsara code maimaitawa. Saboda haka, da sake zagayowar na shirye-shirye - shi ne akai-akai amfani da su yi aikin, suka shirya tare da taimakon harshe albarkatu.

Pascal shirye-shirye da harshen hada da wani yawan kayayyaki:

• ga - maimaita tare da siga.
• yayin - An maimaita tare da na kafin lokaci;
• maimaita ... har sai - ya mayar da wani postcondition.

Duk da seeming sauki da kuma tsabta daga cyclic Tsarin, novice shirye-shirye na fuskantar wani yawan matsaloli a su aiwatar. A mafi girma wahala ne fitarwa saitin yanayi na sake zagayowar. A wannan girmamawa, da kirgawa ga bayani ne mafi saukin ganewa.

tsarin

Don rikodin sake tsarin da siga, kana bukatar ka gwada da wadannan code:

DON {a}: = {b } TO {c} YI {d}.

A misali na zurfin kalmomi na harshen domin saukaka babban birnin kasar haruffa, a yi, za ka iya amfani da wani layi mark. Used canji da kuma aiki da aka bã a curly baka. Su na nufin:

• {A} - m na kowane irin countable, sau da yawa lamba;
• {B}, {c} - magana countable type, guda kamar yadda {a}.
• {D} - sabani sadarwarka / harshen aiki, wanda kuma ake kira da madauki jiki.

Yin zane ga, Pascal calculates darajar {b}, sets {a}: = {c} , sai farawa Redo:

• tabbaci na da yanayin {b} <= {c} , a da kisa sake zagayowar tana daina aiki.
• jefa sadarwarka {d}.
• kara darajar {a} a naúrar ba, Ina nufin {a}: = {a} + 1.

Saboda yawan maimaitawar a cikin jiki domin sananne a wannan shiri koma zuwa deterministic hawan keke.

misali

Don gane da yadda za a za'ayi domin, da dai sauransu, shi ne wani misali, da code a Pascal ga "dummies".

• s: = 0.
• ga wani: = 1 zuwa 5 yi
• fara
• s: = s + wani.
• ƙare.
• writeln (s).

Nazarin da aka rubuta umarnin iya rubuta dabi'u a cikin kowane iteration:

• 1st iteration: a = 1; s = 1;
• 2nd iteration: a = 2. s = 3.
• Uku iteration: a = 3. s = 6;
• 4-th iteration: a = 4; s = 10;
• 5th iteration: a = 5; s = 15.

A sakamakon haka, da mai amfani da gani a kan allon da lambar "15" - Naira Miliyan Xari da lambobi daga 1 zuwa 5.

Don yin farko shirin mafi m, maye gurbin da lambar 1 da 5 canji.

kowa kuskure

A lokacin da ka yi amfani da wani ga madauki, Pascal bukatar hankali da dabi'u na {a}, {b}, {c}. Idan ba ka cika da dokoki da rubuce-rubuce da shirye-shirye, da mai tarawa zai bayar da rahoton wani kuskure. Biyar da irin wannan dokoki.

1. Counter (zagayowar siga) {a} aka bai da wani lamba.
2. A dabi'u {b} da kuma {c} Dole ne ma da wani lamba type. Alal misali, shi wajibi ne yin lissafi da dabi'u na kwana, a radians daga 0 to p. Amma na gaba code shigarwa zai zama daidai ba ga wani: = 0 to pi yi. Magani - yi amfani da Ƙididdigar aiki trunc () da zagaye (). Da farko discards da fractional ɓangare na real lambar, na biyu - zagaye da shi zuwa ga mafi kusa lamba.
3. Idan mai amfani ya yi kuskure, kuma dole {b} <{c}, {d} sadarwarka ba zai yi aiki.
4. Bayan yin madauki counter {a} iya zama wani darajar. Ko da yake shi ne counterintuitive, amma a yi, {a} <> {c} . Kammalawa: kada ku jũya {a} bayan da zane ga.
5. A jikin madauki (cewa shi ne, bayan da kalmomin yi) ba da shawarar yin amfani da wani kalamai cewa gyara da siga dabi'u {a}. Bayan wannan mulki ba zai haifar da wani kuskure ba, amma da dabaru na shirin da zai karye.

Wadannan mulki ne na kowa da kuma yayi dace da "mai kyau hali" a shirye-shirye: shi ya dace da aiki tare da code, dole ne ka rubuta madauki jiki aiki ne ba a farkon shafi. Alal misali, yin 2-3 sarari a kan hagu ko ta amfani da Tab key.

Wannan umurni ne m ba kawai ga Pascal harshe. Domin da "dummies", shi ba ka damar da sauri sami da kuma gyara kuskure a cikin umarnin.

Common ayyuka

Misali kana so ka yi wata arya aiki na da tsari f (x) = 3 * x + 15, cewa shi ne ya sami tebur daga M aiki dabi'u a cikin kewayon [x _1; x _2] inda x ₁ da kuma x ₂ - m da kuma iyakar dabi'u na shaida. Don warware wannan da kuma irin matsalolin taimaka wajen tsara don. Pascal ya bada shawarar cewa ku rubũta da code kamar haka:

• ga wani: = 1 zuwa M yi
• fara
• x: = x1 + (x2- x1) * (DUNIYA 1) / (M-1).
• f: = 3 * x + 15;
• writeln (x, '', f );
• karshen.

Tun da increment x ba a saita, da ya kasance hujjarsu darajar da aka lasafta a lokacin kowace iteration na shirin amfani da dabara: x: = x1 + (x2- x1) * (DUNIYA 1) / (M-1).

A sake zagayowar a sake zagayowar

A ra'ayi na cewa a cikin tsarin da aka jiyar da su yi amfani da wani daga cikin aiki a yarda a saka ta jiki a cikin wani zagayowar for. Pascal yana da wani misali bayanin domin aiki, kama da sauran shirye-shirye harsuna:

• DON {a}: = {b } TO {c} YI
• DON {A1}: = {B1 } TO {C1} YI

Don tsara aiki daidai, dole ne ka cika da yanayin: counters a kowane sake zagayowar ya zama daban-daban. In ba haka ba, na ciki madauki zai canza darajar da m madauki, wanda zai kai ga ma'ana kurakurai.