JAVA_basic lecture source code

Author: yjmini

.gitignore

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+### IntelliJ IDEA ###
+out/
+!**/src/main/**/out/
+!**/src/test/**/out/
+
+### Eclipse ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+bin/
+!**/src/main/**/bin/
+!**/src/test/**/bin/
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+
+### VS Code ###
+.vscode/
+
+### Mac OS ###
+.DS_Store

.idea/.gitignore

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+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

.idea/misc.xml

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+//TIP To <b>Run</b> code, press <shortcut actionId="Run"/> or
+// click the <icon src="AllIcons.Actions.Execute"/> icon in the gutter.
+public class Main {
+    public static void main(String[] args) {
+        //TIP Press <shortcut actionId="ShowIntentionActions"/> with your caret at the highlighted text
+        // to see how IntelliJ IDEA suggests fixing it.
+        System.out.printf("Hello and welcome!");
+
+        for (int i = 1; i <= 5; i++) {
+            //TIP Press <shortcut actionId="Debug"/> to start debugging your code. We have set one <icon src="AllIcons.Debugger.Db_set_breakpoint"/> breakpoint
+            // for you, but you can always add more by pressing <shortcut actionId="ToggleLineBreakpoint"/>.
+            System.out.println("i = " + i);
+        }
+    }
+}

.idea/modules.xml

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+package access;
+
+public class BankAccount {
+
+    private int balance;
+
+    public BankAccount() {
+        balance = 0;
+    }
+
+    //public 메서드: deposit
+    public void deposit(int amount) {
+        if (isAmountValid(amount)) {
+            balance += amount;
+        } else {
+            System.out.println("유효하지 않은 금액입니다.");
+        }
+    }
+
+    //public 메서드: withdraw
+    public void withdraw(int amount) {
+        if (isAmountValid(amount) && balance - amount >= 0) {
+            balance -= amount;
+        } else {
+            System.out.println("유효하지 않은 금액이거나 잔액이 부족합니다.");
+        }
+    }
+
+    //public 메서드: getBalance
+    public int getBalance() {
+        return balance;
+    }
+    private boolean isAmountValid(int amount) {
+        //금액이 0보다 커야함
+        return amount > 0;
+    }
+}

.idea/uiDesigner.xml

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+package access;
+
+public class BankAccountMain {
+
+    public static void main(String[] args) {
+        BankAccount account = new BankAccount();
+        account.deposit(10000);
+        account.withdraw(3000);
+        System.out.println("balance = " + account.getBalance());
+    }
+}

java-basic.iml

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+package access;
+
+public class Speaker {
+    private int volume;
+
+    Speaker(int volume) {
+        this.volume = volume;
+    }
+
+    void volumeUp() {
+        if (volume >= 100) {
+            System.out.println("음량을 증가할 수 없습니다. 최대 음량입니다.");
+        } else {
+            volume += 10;
+            System.out.println("음량을 10 증가합니다.");
+        }
+    }
+
+    void volumeDown() {
+        volume -= 10;
+        System.out.println("volumeDown 호출");
+    }
+
+    void showVolume() {
+        System.out.println("현재 음량: " + volume);
+    }
+}

src/Main.java

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+package access;
+
+public class SpeakerMain {
+    public static void main(String[] args) {
+        Speaker speaker = new Speaker(90);
+        speaker.showVolume();
+
+        speaker.volumeUp();
+        speaker.showVolume();
+
+        speaker.volumeUp();
+        speaker.showVolume();
+
+        //필드에 직접 접근
+        System.out.println("volume 필드 직접 접근 수정");
+        //speaker.volume = 200;
+        speaker.showVolume();
+    }
+}

src/access/BankAccount.java

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+package access.a;
+
+public class AccessData {
+
+    public int publicField;
+    int defaultField;
+    private int privateField;
+
+    public void publicMethod() {
+        System.out.println("publicMethod 호출 " + publicField);
+    }
+
+    void defaultMethod() {
+        System.out.println("defaultMethod 호출 " + defaultField);
+    }
+
+    private void privateMethod() {
+        System.out.println("privateMethod 호출 " + privateField);
+    }
+
+    public void innerAccess() {
+        System.out.println("내부 호출");
+        publicField = 100;
+        defaultField = 200;
+        privateField = 300;
+        publicMethod();
+        defaultMethod();
+        privateMethod();
+    }
+}

src/access/BankAccountMain.java

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+package access.a;
+
+public class AccessInnerMain {
+    public static void main(String[] args) {
+        AccessData data = new AccessData();
+        //public 호출 가능
+        data.publicField = 1;
+        data.publicMethod();
+
+        //같은 패키지 default호출 가능
+        data.defaultField = 2;
+        data.defaultMethod();
+
+        //private 호출 불가
+        //data.privateField = 3;
+        //data.privateMethod();
+
+        data.innerAccess();
+    }
+}

src/access/Speaker.java

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+package access.a;
+
+public class PublicClass {
+    public static void main(String[] args) {
+        PublicClass publicClass = new PublicClass();
+        DefaultClass1 class1 = new DefaultClass1();
+        DefaultClass2 class2 = new DefaultClass2();
+    }
+}
+
+class DefaultClass1 {
+
+}
+
+class DefaultClass2 {
+
+}

src/access/SpeakerMain.java

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+package access.a;
+
+public class PublicClassInnerMain {
+    public static void main(String[] args) {
+        PublicClass publicClass = new PublicClass();
+        DefaultClass1 class1 = new DefaultClass1();
+        DefaultClass2 class2 = new DefaultClass2();
+    }
+}