Java

    ์บก์Аํ™”

    ์บก์Аํ™”

    Encapsulation ( ์บก์Аํ™” ) ์ œํ•œ์ž ์ œํ•œ์ž (modifier) ํด๋ž˜์Šค, ๋ณ€์ˆ˜, ๋ฉ”์„œ๋“œ ์„ ์–ธ๋ถ€์™€ ํ•จ๊ผ ์‚ฌ์šฉ๋˜์–ด ๋ถ€๊ฐ€์ ์ธ ์˜๋ฏธ๋ฅผ ๋ถ€์—ฌ ์ ‘๊ทผ ์ œํ•œ์ž : private, default(package), protected, public static : ํด๋ž˜์Šค ๋ ˆ๋ฒจ์˜ ์š”์†Œ ์„ค์ • final : ์š”์†Œ๋ฅผ ๋”์ด์ƒ ์ˆ˜์ •ํ•  ์ˆ˜ ์—†๊ฒŒ ํ•จ abstract: ์ถ”์ƒ ๋ฉ”์„œ๋“œ ๋ฐ ์ถ”์ƒ ํด๋ž˜์Šค ์ž‘์„ฑ synchronized: ๋ฉ€ํ‹ฐ ์Šค๋ ˆ๋“œ์—์„œ์˜ ๋™๊ธฐํ™” ์ฒ˜๋ฆฌ ์ ‘๊ทผ ์ œํ•œ์ž public class Parent{ public int publicVar;protected int protectedVar;int defaultVar;private int privVar; public void useMember(){ this.publicVar=10;..

    ๋‹คํ˜•์„ฑ

    Polymorphism ์ •์˜ ๋‹คํ˜•์„ฑ์ด๋ž€ ํ•˜๋‚˜์˜ ๊ฐ์ฒด๊ฐ€ ๋งŽ์€ ํ˜•(ํƒ€์ž…)์„ ๊ฐ€์งˆ ์ˆ˜ ์žˆ๋Š” ์„ฑ์งˆ์ด๋‹ค. ๋‹คํ˜•์„ฑ์€, ์ƒ์†๊ด€๊ณ„์— ์žˆ์„ ๋•Œ ์กฐ์ƒํด๋ž˜์Šค์˜ ํƒ€์ž…์œผ๋กœ ์ž์‹ ํด๋ž˜์Šค ๊ฐ์ฒด๋ฅผ ๋ ˆํผ๋Ÿฐ์Šค ํ•  ์ˆ˜ ์žˆ๋‹ค. ex) ํŒฅ๋ถ•์–ด๋นต is a ๋ถ•์–ด๋นต | ์Šˆํฌ๋ฆผ๋ถ•์–ด๋นต is a ๋ถ•์–ด๋นต | ํ”ผ์ž ๋ถ•์–ด๋นต is a ๋ถ•์–ด๋นต ํ™œ์šฉ ๋‹คํ˜•์„ฑ์œผ๋กœ ๋‹ค๋ฅธ ํƒ€์ž…์˜ ๋ฐ์ดํ„ฐ๋ฅผ ํ•˜๋‚˜์˜ ๋ฐฐ์—ด๋กœ๊ด€๋ฆฌํ•  ์ˆ˜ ์žˆ๋‹ค public ArrayList(int initialCapacity){ if(initialCapcity>0){this.elementData = new Object [initialCapacity];} else if (initialCapacity ==0 ){this.elementData = EMPTY_ELEMENTDATA;} else{throw new Illeg..

    ์ƒ์†

    ์ƒ์†

    Inheritance (์ƒ์†) ๐Ÿคฆ๐Ÿป‍โ™€๏ธ ์ƒ์†์˜ ๊ด€๊ณ„๋Š” is - a ๊ด€๊ณ„์ด๋‹ค ์ •์˜ ์ƒ์†์€ ๊ธฐ์กด ํด๋ž˜์Šค์˜ ์ž์‚ฐ (๋งด๋ฒ„)๋ฅผ ์ž์‹ ํด๋ž˜์Šค์—์„œ ์žฌ์‚ฌ์šฉ ํ•˜๊ธฐ ์œ„ํ•ด ์“ฐ์ธ๋‹ค. ํ˜„์‹ค์—์„œ์™€๋Š” ๋ฐ˜๋Œ€๋กœ, ๋ถ€๋ชจ๊ฐ€ ์ž์‹์—๊ฒŒ ์ƒ์†์‹œ์ผœ์ฃผ๋Š” ๊ฒƒ์ด ์•„๋‹ˆ๋ผ ์ž์‹์ด ๋ถ€๋ชจ๋‹˜ ํด๋ž˜์Šค๋ฅผ ์ƒ์†ํ•˜๋Š”๊ฒƒ์ด๋‹ค (๋ถˆํšจ์ž์‹) ๊ธฐ์กด ํด๋ž˜์Šค์˜ ๋งด๋ฒ„๋ฅผ ๋ฌผ๋ ค๋ฐ›๊ธฐ ๋•Œ๋ฌธ์— ์ฝ”๋“œ๋ฅผ ์ ˆ๊ฐํ•  ์ˆ˜ ์žˆ๊ณ  ์œ ์ง€ ๋ณด์ˆ˜๊ฐ€ ํŽธ๋ฆฌํ•˜๋‹ค ํ‚ค์›Œ๋“œ : extends public class ๋ถ•์–ด๋นตํ‹€ { String product_name; String fillings; int age ; //unit - min void coolDown(); void eaten (); } public class ๋ถ•์–ด๋นต extends ๋ถ•์–ด๋นตํ‹€{ boolean isCarp ; void curse() {} } ๐Ÿงธ์ƒ์†..

    ์ถ”์ƒํ™”

    ์ถ”์ƒํ™”

    Abstraction ํด๋ž˜์Šค๋Š” ์ถ”์ƒํ™”์˜ ์ตœ์†Œ ๋‹จ์œ„์ด๋‹ค ์†์„ฑ๊ณผ ๊ธฐ๋Šฅ์„ ์ถ”์ƒํ™” ํ•˜์—ฌ ํด๋ž˜์Šค๋กœ ๋งŒ๋“ค๊ณ , ์ด ํด๋ž˜์Šค๋ฅผ ๊ตฌ์ฒดํ™” ํ•˜๋ฉด ํ”„๋กœ๊ทธ๋žจ์˜ ๊ฐ์ฒด๊ฐ€ ๋œ๋‹ค Practice Problem: ์•„๋ž˜ ํด๋ž˜์Šค๋“ค์˜ ๊ณตํ†ต ๋ถ„๋ชจ๋ฅผ ๋ฝ‘์•„์„œ ์ƒ์† ๊ตฌ์กฐ๋ฅผ ๋งŒ๋“ค์–ด ๋ณด์ž public class DiselSuv{ private int curX, curY; public void reportPosition(){System.out.printf("ํ˜„์žฌ ์œ„์น˜: (%d, %d)%n" ,curX, curY );} public void addFuel(){System.out.printf("์ฃผ์œ ์†Œ์—์„œ ๊ธ‰์œ ");} } public class ElectricCar{ private int curX, curY; public void reportPosition()..

    ๊ฐ์ฒด ์ง€ํ–ฅ ํ”„๋กœ๊ทธ๋ž˜๋ฐ

    ๊ฐ์ฒด ์ง€ํ–ฅ ํ”„๋กœ๊ทธ๋ž˜๋ฐ

    ๊ฐ์ฒด ์ง€ํ–ฅ ํ”„๋กœ๊ทธ๋ž˜๋ฐ ํ˜„์‹ค ์„ธ๊ณ„ ๊ฐ์ฒด, ํด๋ž˜์Šค, ๊ฐ์ฒด์˜ ๊ด€๊ณ„ ํ˜„์‹ค์˜ ๊ฐ์ฒด๊ฐ€ ๊ฐ–๋Š” ์†์„ฑ๊ณผ ๊ธฐ๋Šฅ์€ ์ถ”์ƒํ™” ๋˜์–ด ํด๋ž˜์Šค์— ์ •์˜๋˜๊ณ , ํด๋ž˜์Šค๋Š” ๊ตฌ์ฒดํ™” ๋˜์–ด ํ”„๋กœ๊ทธ๋žจ์˜ ๊ฐ์ฒด(instance, object) ๊ฐ€ ๋œ๋‹ค. EX: ๋ถ•์–ด๋นต ํ‹€ == type ๊ทœ์ • ๋ถ•์–ด๋นต == ๊ฐ์ฒด ์ฆ‰, ํด๋ž˜์Šค๋Š” ๊ฐ์ฒด๋ฅผ ์ •์˜ํ•ด ๋†“์€ ๊ฐ์ฒด์˜ ์„ค๊ณ„๋„ or ํ‹€๋กœ ์ง์ ‘ ์‚ฌ์šฉํ•  ์ˆ˜ ์—†๊ณ  ์ง์ ‘ ์‚ฌ์šฉ๋˜๋Š” ๊ฐ์ฒด๋ฅผ ๋งŒ๋“ค๊ธฐ ์œ„ํ•œ "ํ‹€" ์„ ์ œ๊ณตํ•  ๋ฟ์ด๋‹ค. ๋ฐ˜๋ฉด**, ๊ฐ์ฒด** (instance, object ) ๋Š” ํด๋ž˜์Šค๋ฅผ ๋ฐ์ดํ„ฐ ํƒ€์ž…์œผ๋กœ ๋ฉ”๋ชจ๋ฆฌ์— ์ƒ์„ฑ๋œ ๊ฒƒ์ด๋‹ค. /* ๋ถ•์–ด๋นตํ‹€ ํด๋ž˜์Šค๋Š” ํ‹€์ผ ๋ฟ, * ์ง์ ‘์‚ฌ์šฉํ• ์ˆ˜ ์—†๋‹ค*/ Public class ๋ถ•์–ด๋นตํ‹€{ // ๋งด๋ฒ„ ๋ณ€์ˆ˜: String Name, Fillings ; int age; //unit: min // ๋ฉ”..

    Class Case Exception

    Class Case Exception

    Class Case Exception import java.util.Arrays; class Burger{ String name; int price; Burger(String name, int price){} } public class Test01 { public static void main(String[] args) { Burger[] burgers = new Burger[3]; burgers[0] = new Burger("1957",6000); burgers[1] = new Burger("๋”๋ธ”๋ถˆ๊ณ ๊ธฐ",7000); burgers[2] = new Burger("ํ•œ์šฐ๋ฒ„๊ฑฐ", 8000); Arrays.sort(burgers); //Exception occurs } } ์œ„ ์ฝ”๋“œ๋ฅผ ์‹คํ–‰ ์‹œํ‚ค๋ฉด ClassCas..