Ichaza indlela umdwelisi wenkqubo we-C adala ngayo, avule, kwaye avale ifayile yokubhaliweyo, okanye ifayile yokubini.
Ifayile, ithetha uthotho lwee-bytes, nokuba yifayile yokubhaliweyo okanye ifayile yokubini, C Language, ayinikezeli kuphela ukufikelela kwinqanaba eliphezulu lemisebenzi, kodwa inikezela ngesiseko (OS) umnxeba wokucubungula iifayile kwisixhobo sokugcina. .Esi sahluko siya kuchaza iminxeba ebalulekileyo kulawulo lwamaxwebhu.
Vula ifayile
Ngesiqhelo usebenzisa i fopen () umsebenzi ukwenza ifayile entsha okanye ukuvula ifayile esele ikhona, le fowuni iqalisa into yodidi lwe FILE equlethe lonke ulwazi oluyimfuneko ukulawula ukuhamba.Nantsi iprototype yalo msebenzi wefowuni:
FILE *fopen ( const char * igama lefayile , const char * indlela );
Apha igama lefayile luluhlu lokubiza ifayile, ixabiso lendlela yofikelelo inokuba lelinye lamaxabiso alandelayo:
| ipateni | inkcazelo |
| r | Vula ifayile yokubhaliweyo ekhoyo evumela ukuba ifundwe. |
| w | Vula ifayile yokubhaliweyo evumela ukubhala kwifayile.Ukuba ifayile ayikho, ifayile entsha yenziwe.Apha, inkqubo yakho ibhala umxholo ukusuka ekuqaleni kwefayile.Ukuba ifayile ikhona, iya kucuthwa ibe nguziro ubude kwaye iphinde ibhalwe. |
| a | Vula ifayile yombhalo kwaye ubhale kwifayile kwimodi yokudibanisa.Ukuba ifayile ayikho, ifayile entsha yenziwe.Apha, inkqubo yakho idibanisa umxholo kwiifayile osele unazo. |
| r+ | Vula ifayile yokubhaliweyo ekuvumela ukuba ufunde kwaye ubhale ifayile. |
| w+ | Vula ifayile yokubhaliweyo ekuvumela ukuba ufunde kwaye ubhale ifayile.Ukuba ifayile sele ikhona, ifayile inqunyulwa ibe ngu-zero ubude, kwaye ukuba ifayile ayikho, ifayile entsha yenziwe. |
| a+ | Vula ifayile yokubhaliweyo ekuvumela ukuba ufunde kwaye ubhale ifayile.Ukuba ifayile ayikho, ifayile entsha yenziwe.Ukufundwa kuqala ekuqaleni kwefayile, kwaye ukubhala kukwimowudi yesihlomelo. |
Ukuba kuqwalaselwe ifayile yokubini, sebenzisa le ndlela yofikelelo ilandelayo ukubuyisela okungasentla:
"rb", "wb", "ab", "rb+", "r+b", "wb+", "w+b", "ab+", "a+b"
ifayile evaliweyo
Ukuvala ifayile, nceda usebenzise i fclose() umsebenzi.Iprototype yomsebenzi imi ngolu hlobo lulandelayo:
int fclose ( FILE * fp );
- Ukuba ifayile ivalwe ngempumelelo, umsebenzi wefclose () ubuyisela u-zero, kwaye ukuba impazamo ibuyisela i-EOF.Lo msebenzi, enyanisweni, ususa idatha kwi-buffer, ivala ifayile, kwaye ikhuphe yonke imemori esetyenziselwa loo fayile.I-EOF isoloko ichazwa kwi-header file stdio.h
Ilayibrari eqhelekileyo ye-C ibonelela ngemisebenzi eyahlukeneyo yokufunda nokubhala iifayile ngabalinganiswa okanye njengomtya wobude obusisigxina.
Bhala kwifayile
Nantsi eyona misebenzi ilula yokubhala abalinganiswa kumjelo:
int fputc ( int c , FILE *fp );
Umsebenzi fputc () ubhala ixabiso lomlinganiswa we parameter c kumjelo wemveliso ekhomba kuwo ifp.Ukuba ukubhala kuphumelele, ibuyisela uphawu olubhaliweyo kunye ne-EOF ukuba kwenzeka impazamo.Ungasebenzisa lo msebenzi ulandelayo ukubhala umtya ophela nge-null kumsinga:
int fputs ( const char *s , FILE *fp );
Umsebenzi fputs () ubhala umtya s kumjelo wemveliso apho ifp ikhomba khona.Ukuba ukubhala kuphumelele, ibuyisela ixabiso elingeyo-negative kunye ne-EOF ukuba kukho impazamo.Ungasebenzisa kwakhona umsebenzi we int fprintf (IFILE * fp, const char * ifomathi,...) ibhala umtya kwifayile.Zama lo mzekelo ulandelayo:
Qaphela: Qiniseka ukuba unoluhlu lwe-tmp olukhoyo, kwaye ukuba alukho, kufuneka ulwenze kwikhompyuter yakho kuqala.
/ tmp idla ngokuba lulawulo lwexeshana kwindlela yeLinux.Ukuba usebenzisa inkqubo yeWindows, kufuneka uyiguqule kulawulo olukhoyo kwindawo yendawo, efana ne: C: \ tmp, D: \ tmp, njl.
umzekelo ophilayo
#zibandakanyaint main () {IFILE *fp = NULL;fp = fopen ("/tmp/test.txt ", "w+");fprintf (fp , "Olu luvavanyo lwefprintf...\n ");fputs ("Oku kuvavanyelwa iifputs...\n ", fp );vala (fp);}
Xa ikhowudi engentla idityanisiwe kwaye iphunyeziwe, yenza ifayile entsha test.txt kwi/tmp directory.Kwaye ubhalela imigca emibini esebenzisa imisebenzi emibini eyahlukeneyo.Masifunde le fayile ngokulandelayo.
Funda ifayile
Okulandelayo ngowona msebenzi ulula wokufunda unobumba omnye kwifayile:
int fgetc ( FILE * fp );
fgetc () umsebenzi ufunda umsebenzi osuka kwifayile yegalelo apho ifp ikhomba khona.Ixabiso lokubuyisela luphawu olufundiweyo kunye ne-EOF ukuba kukho impazamo.Umsebenzi olandelayo ikuvumela ukuba ufunde umtya kumsinga:
char *fgets ( char *buf , int n , FILE *fp );
Umsebenzi fgets () ufunda n-1 abasebenzi ukusuka kumjelo wegalelo elathiswe ngu fp.Ikhuphela umtya ofundiweyo kwibuffer buf kwaye ifakela unobumba ongenanto ekupheleni ukuphelisa umtya.
Ukuba lo msebenzi udibana nombhalo owaphukileyo welayini '\ n' okanye i-EOF yesiphelo sefayile phambi kokufunda umsebenzi wokugqibela, emva koko ibuyiselwe kuphela kumagama afundiweyo, ukuquka ikhefu lomgca.Ungasebenzisa kwakhona i-int fscanf (IFILE * fp, const char * format,...) umsebenzi wokufunda umtya kwifayile, kodwa iyeke ukufunda xa idibana nesithuba sokuqala kunye nekhefu lomgca.
umzekelo ophilayo
#zibandakanyaint main () {IFILE *fp = NULL;char buff [255];fp = fopen ("/tmp/test.txt ", "r");fscanf (fp , "%s ", buff);printf ("1: %s \n ", buff );fgets (buff, 255, (IFILE *)fp);printf ("2: %s \n ", buff );fgets (buff, 255, (IFILE *)fp);printf ("3: %s \n ", buff );vala (fp);}
Xa ikhowudi engentla idityanisiwe kwaye iphunyeziwe, ifunda iifayile ezenziwe kwicandelo langaphambili, ivelisa ezi ziphumo zilandelayo:
1: Le 2: ivavanya i-fprintf...
3: Olu luvavanyo lweefputs...
Okokuqala, indlela ye fscanf () ifunda kuphela Oku .kuba idibana nesithuba ngasemva.Okwesibini, biza i-functon fgets () ukufunda inxalenye eseleyo kude kube sekupheleni komgca.Ekugqibeleni, fowunela fgets () ukufunda umqolo wesibini ngokupheleleyo.
Umsebenzi weBinary I / O
Imisebenzi emibini elandelayo isetyenziselwa igalelo lokubini kunye nemveliso:
size_t fread (ingabikho *ptr, size_t size_of_elements, size_t number_of_elements, FILE *a_file);size_t fwrite (const void *ptr , size_t size_of_elements , size_t number_of_elements , FILE *ifayile );
Yomibini imisebenzi ifundeka kwaye ibhale kwiibhloko zokugcina-ngokuqhelekileyo i-arrays okanye izakhiwo.
Ngaphezulu malunga nefayile ye-C yokufunda nokubhala yeye-HDV Phoelectron Technology Ltd., umsebenzi wobugcisa besoftware.Kwaye inkampani yezixhobo ezinxulumene nenethiwekhi (ezifana ne: ACI-ONU/ unxibelelwanoI-ONU/ okrelekreleI-ONU/ ifayibhaI-ONU, njl.njl.) idibanise iqela elinamandla lesoftware, kuye wonke umthengi enze iimfuno ezikhethekileyo abazifunayo, zivumele iimveliso zethu ukuba zikrelekrele kwaye zihambele phambili.