scanf函数探讨（discussion on scanf function）

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1、scanf函数探讨（Discussiononscanffunction）Discussiononscanffunction:1.blanksymbolproblem#include(main){Inta;Printf("inputthedata");Scanf(%d,&a);//heremorethanacarriagereturnPrintf("%d",a);Return0;}Asaresult,twonumbersareenteredbeforetheendoftheprogram,nottheexpectedone.Why?Reason

2、:whenwhitespaceends,scanfskipswhitespacetoreadthenextcharacter,soyoumustenteranumberagain.Herethewhitespaceincludingspace,tab,newline,carriagereturnandformfeed.Soifyouusescanf("%d","&a"),thesameproblemwilloccur.Solution:thiskindofmistakeismostlyinputcarelessly,justpaymoreattentiontoit.Thi

3、sproblemisnotgood,check,compilenoproblem,ablankisnoteasytosee.Whenyourprogramappearsaboveproblems,checkityourself.2.bufferissuesThisisaveryeasyplacetogowrong,andImissitmanytimes.#include(main){Intn=5;Charc[n];For(inti=0;I

4、CThenthecyclewillendinadvanceReason:afterenteringaandthefirstcarriagereturn,theAandthecarriagereturnareleftinthebuffer.ThefirstscanfreadstheA,butthereisaleftintheinputbuffer,andthesecondscanfreadsthe.ThenenterBandsecondcarriagereturns.Similarly,thethirdscanfreadstheB,andthefourthscanf

5、readsthesecondcarriagereturncharacters.ThefifthreadstheC.Sothefivescanfwereexecutedanddidn'tendearly.Onlysomescanfreadthecarriagereturn.Solution:changetheprogramtojustthis:For(I=0;I

6、tdio.h>(main){Charc[5];Gets(C);Printf(C);Return0;}Butnote:thisfunctionautomaticallyconvertsyourlasthitreturntocharacter''.Ifyourinputexceedsthesizeofthearray,anerrorwilloccur.Theparameterinputtypemismatchforthe3.scanf()functionThisiswhatIsawontheCSDNforum,whichissometimespuzzling.#inclu

7、de(main){Inta=123;Charc='t';Printf("input");Scanf("%d%c","&a","&c");Scanf("%d%c","&a","&c");Scanf("%d%c","&a","&c");Printf("%d%c","a","C");Return0;}Whenyouenteraenter,youwillskipthefollowing2scanfstatements,andoutputdirectlytoOnehundredandtwenty-three