Pranyatan kondisional

1. if-elsePratelan

Program ora bakal migunani banget yen padha nindakake perkara sing padha, preduli saka owah-owahan kahanan eksternal. Sawijining program kudu bisa adaptasi karo kahanan sing beda-beda lan njupuk tindakan tartamtu ing sawetara kahanan, lan tumindak kanthi beda ing kahanan liyane.

Ing Jawa, iki rampung karo statement kondisional , sing nggunakake tembung kunci khusus sing ngidini sampeyan nglakokake blok perintah sing beda-beda gumantung saka nilai sing bener saka sawijining kondisi.

Pranyatan kondisional dumadi saka telung perangan: kaanan , pratelan 1 lan pratelan 2 . Yen kondisi kasebut bener, mula statement 1 dieksekusi. Yen ora, statement 2 dieksekusi. Loro-lorone printah ora tau dieksekusi. Punika tampilan umum saka statement iki:

if (condition)
   statement 1;
else
   statement 2;

Iku cukup dingerteni yen ditulis ing basa Inggris prasaja kaya iki:

If condition is true, then
   execute statement 1;
otherwise
   execute statement 2;

Tuladha:

int age = 17;
if (age < 18)
   System.out.println("You are still a child");
else
   System.out.println("You are now an adult");

You are still a child

int temperature = 5;
if (temperature < 0)
   System.out.println("It's freezing outside");
else
   System.out.println("It's warm");

It's warm

int age = 18;
if (age == 18)
   System.out.println("You've been drafted for military service");
else
   System.out.println("Report for duty anyway");

You've been drafted for military service

2. Blok statement

Yen kondisi wis wareg (utawa ora) lan sampeyan pengin program kanggo nglakokaké sawetara printah, sampeyan bisa gabungke menyang blok .

Kanggo nggabungake perintah dadi blok, sampeyan "bungkus" nganggo kurung kriting . Mangkene tampilan umume:

{
   statement 1;
   statement 2;
   statement 3;
}

Sampeyan bisa duwe akeh statements sing pengin ing blok. Utawa malah ora ana.

Conto statement if-else sing digabung karo blok statement:

int age = 17;
if (age < 18)
{
   System.out.println("You are still a child");
   System.out.println("Don't talk back to adults");
}
else
{
   System.out.println("You are now an adult");
   System.out.println("And thus ends your youth");
}

You are still a child
Don't talk back to adults

int temperature = 5;
if (temperature < 0)
{
   System.out.println("It's freezing outside");
   System.out.println("Put on a hat");
}
else
   System.out.println("It's warm");

It's warm

int age = 21;
if (age == 18)
   System.out.println("You've been drafted for military service");
else
{
}

3. Wujud cekakan saka ifpratelan

Kadhangkala sampeyan kudu nglakokake siji utawa pernyataan yen kondisi kasebut bener nanging ora ana sing kudu ditindakake yen salah.

Contone, kita bisa nemtokake printah iki: , nanging ora nanggepi yen bis ora kene. Ing Jawa, skenario iki ngidini kita nggunakake wangun sing disingkat: statement tanpa blok.If Bus No. 62 has arrived, then get aboardifelse

Ing tembung liya, yen pratelan kudu dieksekusi mung yen kondisi kasebut bener lan ora ana prentah sing kudu dieksekusi nalika kondisi kasebut salah, mula sampeyan kudu nggunakake ifpernyataan kasebut, sing ringkes lan ngilangi elseblok kasebut. Katon kaya iki:

if (condition)
   statement 1;

Ing ngisor iki ana telung conto kode sing padha:

int age = 18;
if (age == 18)
{
   System.out.println("You've been drafted for military service");
}
else
{
}

You've been drafted for military service

Program kasebut duwe elseblok, nanging kosong (ora ana pernyataan ing antarane kurung kriting). Sampeyan mung bisa mbusak. Ora ana sing bakal diganti ing program kasebut.

int age = 18;
if (age == 18)
{
   System.out.println("You've been drafted for military service");
}

You've been drafted for military service

int age = 18;
if (age == 18)
   System.out.println("You've been drafted for military service");

You've been drafted for military service