CodeGym /ํ–‰๋™ /All lectures for KO purposes /๋‹คํ˜•์„ฑ, ํŒŒํŠธ 2

๋‹คํ˜•์„ฑ, ํŒŒํŠธ 2

All lectures for KO purposes
๋ ˆ๋ฒจ 1 , ๋ ˆ์Šจ 563
์‚ฌ์šฉ ๊ฐ€๋Šฅ

1. ํ•˜์ง€๋งŒ ๊ทธ๊ฒŒ ๋‹ค๊ฐ€ ์•„๋‹™๋‹ˆ๋‹ค.

ํด๋ž˜์Šค์— ๋‘ ๊ฐœ์˜ ๋‹ค๋ฅธ ๋ฉ”์„œ๋“œ๋ฅผ ํ˜ธ์ถœํ•˜๋Š” ๋ฉ”์„œ๋“œ๊ฐ€ Cow์žˆ๋‹ค๊ณ  ๊ฐ€์ •ํ•ฉ๋‹ˆ๋‹ค . printAll()๊ทธ๋Ÿฌ๋ฉด ์ฝ”๋“œ๋Š” ๋‹ค์Œ๊ณผ ๊ฐ™์ด ์ž‘๋™ํ•ฉ๋‹ˆ๋‹ค.

์•”ํ˜ธ ์„ค๋ช…
class Cow
{
   public void printAll()
   {
      printColor();
      printName();
   }

   public void printColor ()
   {
      System.out.println("I'm a white whale");
   }

   public void printName()
   {
      System.out.println("I'm a cow");
   }
}

class Whale extends Cow
{
   public void printName()
   {
      System.out.println("I'm a whale");
   }
}
public static void main(String[] args)
{
   Whale whale = new Whale ();
   whale.printAll();
}
ํ™”๋ฉด ์ถœ๋ ฅ์€ ๋‹ค์Œ๊ณผ ๊ฐ™์Šต๋‹ˆ๋‹ค.
I'm a white whale
I'm a whale

printAll()ํด๋ž˜์Šค ์˜ ๋ฉ”์„œ๋“œ๊ฐ€ ๊ฐ์ฒด ์— ๋Œ€ํ•ดCow ํ˜ธ์ถœ๋  ๋•Œ ๋ฉ”์„œ๋“œ ์˜ ๋ฉ”์„œ๋“œ ๊ฐ€ ์•„๋‹Œ ํด๋ž˜์Šค์˜ ๋ฉ”์„œ๋“œ๊ฐ€ ์‚ฌ์šฉ๋œ๋‹ค๋Š” ์ ์— ์œ ์˜ํ•˜์‹ญ์‹œ์˜ค .WhaleprintNameWhaleCow

์ค‘์š”ํ•œ ๊ฒƒ์€ ๋ฉ”์„œ๋“œ๊ฐ€ ์ž‘์„ฑ๋œ ํด๋ž˜์Šค๊ฐ€ ์•„๋‹ˆ๋ผ ๋ฉ”์„œ๋“œ๊ฐ€ ํ˜ธ์ถœ๋˜๋Š” ๊ฐ์ฒด์˜ ์œ ํ˜•(ํด๋ž˜์Šค)์ž…๋‹ˆ๋‹ค.

๋น„์ •์  ๋ฉ”์„œ๋“œ๋งŒ ์ƒ์† ๋ฐ ์žฌ์ •์˜ํ•  ์ˆ˜ ์žˆ์Šต๋‹ˆ๋‹ค. ์ •์  ๋ฉ”์„œ๋“œ๋Š” ์ƒ์†๋˜์ง€ ์•Š์œผ๋ฏ€๋กœ ์žฌ์ •์˜ํ•  ์ˆ˜ ์—†์Šต๋‹ˆ๋‹ค.

๋‹ค์Œ์€ Whale์ƒ์† ๋ฐ ๋ฉ”์„œ๋“œ ์žฌ์ •์˜๋ฅผ ์ ์šฉํ•œ ํ›„์˜ ํด๋ž˜์Šค ๋ชจ์Šต์ž…๋‹ˆ๋‹ค.

class Whale
{
   public void printAll()
   {
      printColor();
      printName();
   }

   public void printColor()
 {       System.out.println("I'm a white whale");
   }

   public void printName()
   {
      System.out.println("I'm a whale");
   }
}
๋‹ค์Œ์€ Whale์ƒ์† ๋ฐ ๋ฉ”์„œ๋“œ ์žฌ์ •์˜๋ฅผ ์ ์šฉํ•œ ํ›„์˜ ํด๋ž˜์Šค ๋ชจ์Šต์ž…๋‹ˆ๋‹ค. ์ด์ „ ๋ฉ”์„œ๋“œ์— ๋Œ€ํ•ด ์•Œ์ง€ ๋ชปํ•ฉ๋‹ˆ๋‹ค printName.

2. ํƒ€์ž…์บ์ŠคํŒ…

์—ฌ๊ธฐ์— ๋” ํฅ๋ฏธ๋กœ์šด ์ ์ด ์žˆ์Šต๋‹ˆ๋‹ค. ํด๋ž˜์Šค๋Š” ๋ถ€๋ชจ ํด๋ž˜์Šค์˜ ๋ชจ๋“  ๋ฉ”์„œ๋“œ์™€ ๋ฐ์ดํ„ฐ๋ฅผ ์ƒ์†ํ•˜๊ธฐ ๋•Œ๋ฌธ์— ์ž์‹ ํด๋ž˜์Šค์˜ ๊ฐœ์ฒด์— ๋Œ€ํ•œ ์ฐธ์กฐ๋Š” ๋ถ€๋ชจ ํด๋ž˜์Šค (๋ฐ ๋ถ€๋ชจ์˜ ๋ถ€๋ชจ ๋“ฑ )์™€ ์œ ํ˜•์ด ๋™์ผํ•œ ๋ณ€์ˆ˜์— ์ €์žฅ(ํ• ๋‹น)๋  ์ˆ˜ ์žˆ์Šต๋‹ˆ๋‹ค. ์ˆ˜์—…๊นŒ์ง€ Object). ์˜ˆ:

์•”ํ˜ธ ์„ค๋ช…
public static void main(String[] args)
{    Whale whale = new Whale();
   whale.printColor();
}
ํ™”๋ฉด ์ถœ๋ ฅ์€ ๋‹ค์Œ๊ณผ ๊ฐ™์Šต๋‹ˆ๋‹ค.
I'm a white whale
public static void main(String[] args)
{
   Cow cow = new Whale();
   cow.printColor();
}
ํ™”๋ฉด ์ถœ๋ ฅ์€ ๋‹ค์Œ๊ณผ ๊ฐ™์Šต๋‹ˆ๋‹ค.
I'm a white whale
public static void main(String[] args)
{
   Object o = new Whale();
   System.out.println(o.toString());
}
ํ™”๋ฉด ์ถœ๋ ฅ์€ ๋‹ค์Œ๊ณผ ๊ฐ™์Šต๋‹ˆ๋‹ค.
Whale@da435a.

๋ฉ”์„œ๋“œ ๋Š” ํด๋ž˜์Šค toString()์—์„œ ์ƒ์†๋ฉ๋‹ˆ๋‹ค.Object

์ด๊ฒƒ์€ ๋งค์šฐ ๊ท€์ค‘ํ•œ ์†์„ฑ์ž…๋‹ˆ๋‹ค. ์กฐ๊ธˆ ํ›„์— ์‹ค์ œ๋กœ ์‚ฌ์šฉํ•˜๋Š” ๋ฐฉ๋ฒ•์„ ์ดํ•ดํ•˜๊ฒŒ ๋  ๊ฒƒ์ž…๋‹ˆ๋‹ค.


3. ๊ฐ์ฒด์— ๋Œ€ํ•œ ๋ฉ”์„œ๋“œ ํ˜ธ์ถœ

๋ฉ”์„œ๋“œ๊ฐ€ ๋ณ€์ˆ˜์— ๋Œ€ํ•ด ํ˜ธ์ถœ๋˜๋ฉด ๋ฉ”์„œ๋“œ๋Š” ์‹ค์ œ๋กœ ๊ฐœ์ฒด์— ๋Œ€ํ•ด ํ˜ธ์ถœ๋ฉ๋‹ˆ๋‹ค. ์ด ๋ฉ”์ปค๋‹ˆ์ฆ˜์„ ๋™์  ๋ฉ”์„œ๋“œ ๋””์ŠคํŒจ์น˜๋ผ๊ณ  ํ•ฉ๋‹ˆ๋‹ค.

๋‹ค์Œ๊ณผ ๊ฐ™์ด ํ‘œ์‹œ๋ฉ๋‹ˆ๋‹ค.

์•”ํ˜ธ ์„ค๋ช…
public static void main(String[] args)
{
   Whale whale = new Whale();
   whale.printName();
}
ํ™”๋ฉด ์ถœ๋ ฅ์€ ๋‹ค์Œ๊ณผ ๊ฐ™์Šต๋‹ˆ๋‹ค.
I'm a whale
public static void main(String[] args)
{
   Cow cow = new Whale();
   cow.printName();
}
ํ™”๋ฉด ์ถœ๋ ฅ์€ ๋‹ค์Œ๊ณผ ๊ฐ™์Šต๋‹ˆ๋‹ค.
I'm a whale

ํ˜ธ์ถœ๋˜๋Š” ๋ฉ”์„œ๋“œ ์˜ ํŠน์ • ๊ตฌํ˜„ printName()( ์— ์žˆ๋Š” ๋ฉ”์„œ๋“œ Cow๋˜๋Š” ํด๋ž˜์Šค์— ์žˆ๋Š” ๋ฉ”์„œ๋“œ Whale) ์€ ๋ณ€์ˆ˜์˜ ์œ ํ˜•์ด ์•„๋‹ˆ๋ผ ๋ณ€์ˆ˜๊ฐ€ ์ฐธ์กฐํ•˜๋Š” ๊ฐœ์ฒด์˜ ์œ ํ˜•์— ๋”ฐ๋ผ ๊ฒฐ์ •๋ฉ๋‹ˆ๋‹ค.

๋ณ€์ˆ˜ ๋Š” ๊ฐœ์ฒด Cow์— ๋Œ€ํ•œ ์ฐธ์กฐ๋ฅผ ์ €์žฅ Whaleํ•˜๊ณ  ํด๋ž˜์Šค printName()์— ์ •์˜๋œ ๋ฉ”์„œ๋“œ๊ฐ€ Whaleํ˜ธ์ถœ๋ฉ๋‹ˆ๋‹ค.

์ด๊ฒƒ์€ ๊ทธ๋‹ค์ง€ ๋ช…๋ฐฑํ•˜์ง€ ์•Š์Šต๋‹ˆ๋‹ค. ๊ธฐ๋ณธ ๊ทœ์น™์„ ๊ธฐ์–ตํ•˜์‹ญ์‹œ์˜ค.

๋ณ€์ˆ˜์— ๋Œ€ํ•ด ํ˜ธ์ถœํ•  ์ˆ˜ ์žˆ๋Š” ๋ฉ”์„œ๋“œ ์ง‘ํ•ฉ์€ ๋ณ€์ˆ˜ ์œ ํ˜•์— ๋”ฐ๋ผ ๊ฒฐ์ •๋ฉ๋‹ˆ๋‹ค. ๊ทธ๋ฆฌ๊ณ  ํ˜ธ์ถœ๋˜๋Š” ํŠน์ • ๋ฉ”์†Œ๋“œ ๊ตฌํ˜„์€ ๋ณ€์ˆ˜๊ฐ€ ์ฐธ์กฐํ•˜๋Š” ๊ฐ์ฒด์˜ ์œ ํ˜•/ํด๋ž˜์Šค์— ์˜ํ•ด ๊ฒฐ์ •๋ฉ๋‹ˆ๋‹ค.

๋‹น์‹ ์€ ์ด๊ฒƒ์„ ํ•ญ์ƒ ์ ‘ํ•˜๊ฒŒ ๋  ๊ฒƒ์ด๋ฏ€๋กœ ์ด๊ฒƒ์„ ๊ธฐ์–ตํ•˜๋Š” ๊ฒƒ์ด ๋น ๋ฅผ์ˆ˜๋ก ์ข‹์Šต๋‹ˆ๋‹ค.

์ฝ”๋ฉ˜ํŠธ
TO VIEW ALL COMMENTS OR TO MAKE A COMMENT,
GO TO FULL VERSION