20/03/2022
JAVA: D505
(5e) Amfani da API (Karbar Bayanai)
Bayan anyi declaration da initializing na API ko kuma kai tsaye nace instantiating na API, za’a iya karbar bayanai kala-kala daga wajan user, ga wasu daga cikin hanyoyin da ake karbar bayanai da API na scanner:
- Dan karbar kalma daya tak, ana amfani da “next()”
- Dan karbar layi daya, ana amfani da “nextLine()”
- Dan karbar lamba intija (integer) ana amfani da “nextInt()”
- Dan karbar lamba dobil (double) ana amfani da “nextDouble()”
Akwai wasu daban bayyanasu ba, saboda ba’a fiya amfani da su ba!
Idan mai karatu zai iya tunawa a darasin baya mun tsaya akan code dayake instantiating na API din Scanner instantiating kamar haka:
// Instantiating na scanner
Scanner shigarDa = new Scanner(System.in);
“shigarDa” shine lakabin da muka sawa API din scanner; dan haka dashi zamuke amfani tareda daya daga cikin hanyoyin da na lissafa a sama dan karbar bayanai daga wajan user, Misali:
// Dan karbar kalma daya
shigarDa.next();
Wannan code zai bawa user damar shigar da String zuwa manhajarmu; To amma idan kun kula user bai san meze shigarba, zamu iya amfani da statement na output dan sanar da user kalar bayanan da muke bukata:
// Sanar da user bayanan da ake bukata ya shigar
System.out.print(“Shigar da sunan k(a/i): ”);
// Karbar kalma daya daga cikin bayanan da user ya shigar
shigarDa.next();
Idan Compiler tazo kan wannan statement din zata jira har sai user ya shigar da bayanai ya kuma danna maballin “Enter”, Sai dai inaso kula sosai, Java-N-IDE tana da yar matsala wajan karbar bayanai daga wajan user, Kamar yadda na fada (a ka’ida idan user ya shigar da bayanai zai danna maballin “Enter” sau daya dan sanar da manhaja cewa ya gama shigar da bayanan);
To amma ita Java-N-IDE akwai lokutan da sai an danna sau “Biyu”. Yaya ake ganewa?
Daga sama bayan sunan file (anamu misalin “GinaManhaja.java” Compiler ta nuna halin/yanayin da manhajar mu take ciki wanda bature yake kira da “Status (sitatus)” [Duba saman hoto me lamba 57]; Daga cikin status da take nunawa akwai:
1. Running (ranin): wanda yake nufin Compiler tana gwada/gudanarda manhajarmu. Ma’ana compiler tana bin code din manhajarmu tana gudanar da duk abubuwan da muka umarceta da yinsu. [duba hoto me lamba 58]
2. Stopped (sitofd): wanda yake nufin compiler ta gama gwada manhajar mu. Ma’ana compiler ta gama bin dukkan abubuwan da muka umarceta dayinsu. [duba hoto me lamba 59]
Yadda ake ganewa shine idan status ya nuna running kuma ya tsaya, wannan yana nufin compiler tana bukatar user ya shigar da wasu bayanai domin manhjarmu tayi aiki dasu.
Idan kuma ta nuna stopped to ko user ya shigar da bayanai bazasu amfanu ga manhajarmu ba. Ha’ilau dai, wannan matsalace da Java-N-IDE take dauke da ita, idan aka gwada manhajar a computer to za’a fahimci ita bata karbar komai inhar ta nuna stopped a status na manhajar.
Idan kun fahimci wannan, yanzu mun bawa user damar yasa bayanai, to a halin yanzu bayan user ya shigar da bayanansa misali “Na shigar da sunan wannan shafin Gina Manhaja” [Duba hoto me lamba 59], Sai dai ba wani abu daya nuna a output, to ina bayanan suke tafiya?
Ainashin tambayar itace, Yaya zamu amfani bayanan da user ya shigar? Amsar a bude take, ita dai manhaja bata yin komai harsai munce tayi, dan haka, idan muna son ajje bayanan dan amfani dasu sai muyi amfani da variable mu ajje, munsan idan muka zuba bayanan acikin variable zamu iya amfani dasu a duk lokacin da muke so, Kamar haka [duba hoto me lamba 60]
// Declaring na variable nau’in string
// Inkiyar “sunanUser”
String sunanUser;
// Sanar da user bayanan da zai shigar
System.out.print(“Shigar da sunan k(a/i): “);
// Karba da ajje kalma daya (kalmar farko), daga cikin
// bayanan da user zai shigar
sunanUser = shigarDa.next();
// Yanzu zamu iya amfani dashi dai dai da yadda muke amfani da variable
// Misali, fito dashi ta output
System.out.println(sunanUser);
Daga Hoto me lamba 61, rubutu mai launin kore shine wanda aka shigar lokacin da compiler ta bada damar a shigar da bayanai. Rubutu mai launin fari kuma shine wanda compiler ta karba ta ajje a cikin variable;
Me karatu zai iya kula da yadda compiler ta karbi sunan farko daga cikin sunaye biyu dana jerasu a layi guda. Wannan ya tabbatar mana cewa lallai statement na next() kalma daya kawai yake karba ya zubar da sauran.
A wannan lokaci zanso auna fahimtar mai karatu; Inaso mai karatu ya/ta rubuta a comment na wannan darasi, yadda za’a karbi duka kalmomin da user ya shigar, ya fito dashi ta output.
Ku kasance da shafin dan ganin yadda za'a gyara wannan matsalar.