From dad571ede5cc10e69ae01f00c923413c948daaa8 Mon Sep 17 00:00:00 2001
From: stopmin <geemin0@naver.com>
Date: Fri, 7 Jul 2023 22:32:35 +0900
Subject: [PATCH 01/13] solved:Chapter3-1

---
 .../java/Practice/stopmin/Coffeetype.java     | 15 +++++++++
 .../java/Practice/stopmin/FinalPractice.java  | 14 +++++++++
 .../java/Practice/stopmin/HelloWorld.java     | 13 ++++++++
 .../java/Practice/stopmin/ListPractice.java   | 21 +++++++++++++
 .../java/Practice/stopmin/NumberPractice.java | 15 +++++++++
 src/main/java/Practice/stopmin/Sample.java    | 31 +++++++++++++++++++
 .../java/Practice/stopmin/StringPractice.java | 26 ++++++++++++++++
 .../java/Problem/stopmin/Chapter3/Q01.java    |  4 ++-
 src/main/java/Save/Chapter3/Q01.java          |  1 +
 src/main/java/Save/Chapter3/Q03.java          |  1 +
 10 files changed, 140 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/Practice/stopmin/Coffeetype.java
 create mode 100644 src/main/java/Practice/stopmin/FinalPractice.java
 create mode 100644 src/main/java/Practice/stopmin/HelloWorld.java
 create mode 100644 src/main/java/Practice/stopmin/ListPractice.java
 create mode 100644 src/main/java/Practice/stopmin/NumberPractice.java
 create mode 100644 src/main/java/Practice/stopmin/Sample.java
 create mode 100644 src/main/java/Practice/stopmin/StringPractice.java

diff --git a/src/main/java/Practice/stopmin/Coffeetype.java b/src/main/java/Practice/stopmin/Coffeetype.java
new file mode 100644
index 0000000..ae7727b
--- /dev/null
+++ b/src/main/java/Practice/stopmin/Coffeetype.java
@@ -0,0 +1,15 @@
+package Practice.stopmin;
+
+public enum Coffeetype {
+  AMERICANO,
+  ICE_AMERICANO,
+  CAFE_LATTE;
+  public static void main(String[] args) {
+    System.out.println(AMERICANO);
+    for (Coffeetype type : Coffeetype.values()) {
+      System.out.println(type);
+    }
+  }
+};
+
+
diff --git a/src/main/java/Practice/stopmin/FinalPractice.java b/src/main/java/Practice/stopmin/FinalPractice.java
new file mode 100644
index 0000000..8e1aeed
--- /dev/null
+++ b/src/main/java/Practice/stopmin/FinalPractice.java
@@ -0,0 +1,14 @@
+package Practice.stopmin;
+
+import java.util.ArrayList;
+
+public class FinalPractice {
+
+  public static void main(String[] args) {
+    final int n = 10;
+
+    final ArrayList<String> a = new ArrayList<>();
+
+    a.add("hello~");
+  }
+}
diff --git a/src/main/java/Practice/stopmin/HelloWorld.java b/src/main/java/Practice/stopmin/HelloWorld.java
new file mode 100644
index 0000000..f6c9e72
--- /dev/null
+++ b/src/main/java/Practice/stopmin/HelloWorld.java
@@ -0,0 +1,13 @@
+package Practice.stopmin;
+
+public class HelloWorld {
+
+  public static void main(String[] args) {
+    System.out.println("Hello World!"); // 표준 출력
+    System.err.println("Error!"); // 표준 에러 출력
+    System.out.println("숫자" + 3 + "~~~");
+
+    Sample sample = new Sample("EE");
+    sample.myPublic();
+  }
+}
diff --git a/src/main/java/Practice/stopmin/ListPractice.java b/src/main/java/Practice/stopmin/ListPractice.java
new file mode 100644
index 0000000..5dd0609
--- /dev/null
+++ b/src/main/java/Practice/stopmin/ListPractice.java
@@ -0,0 +1,21 @@
+package Practice.stopmin;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+
+public class ListPractice {
+
+  public static void main(String[] args) {
+    ArrayList pitches = new ArrayList();
+    pitches.add("123");
+    pitches.add("312");
+    pitches.add("213");
+    System.out.println(pitches);
+
+    System.out.println("pitches.get(1) = " + pitches.get(1));
+    System.out.println("pitches.size() = " + pitches.size());
+
+    pitches.sort(Comparator.naturalOrder());
+    System.out.println(pitches);
+  }
+}
diff --git a/src/main/java/Practice/stopmin/NumberPractice.java b/src/main/java/Practice/stopmin/NumberPractice.java
new file mode 100644
index 0000000..ce769fa
--- /dev/null
+++ b/src/main/java/Practice/stopmin/NumberPractice.java
@@ -0,0 +1,15 @@
+package Practice.stopmin;
+
+public class NumberPractice {
+
+  public static void main(String[] args) {
+    int age = 21;
+    long count = 102938901283012093L;
+
+    age += 10;
+
+    boolean isTest = true; // is~, has~, can~
+
+  }
+
+}
diff --git a/src/main/java/Practice/stopmin/Sample.java b/src/main/java/Practice/stopmin/Sample.java
new file mode 100644
index 0000000..d1f0ef7
--- /dev/null
+++ b/src/main/java/Practice/stopmin/Sample.java
@@ -0,0 +1,31 @@
+package Practice.stopmin;
+
+public class Sample {
+
+
+  private String message; // 속성, 필드
+
+  public Sample(String message) {
+    this.message = message;
+  }
+
+  public static void main(String[] args) {
+    Sample sample = new Sample("ABDERERER");
+  }
+
+  public void myPublic() {
+    System.out.println(message);
+  }
+
+  protected void myP() {
+
+  }
+
+  private void myP2() {
+
+  }
+
+  void myD() {
+
+  }
+}
diff --git a/src/main/java/Practice/stopmin/StringPractice.java b/src/main/java/Practice/stopmin/StringPractice.java
new file mode 100644
index 0000000..86b2f27
--- /dev/null
+++ b/src/main/java/Practice/stopmin/StringPractice.java
@@ -0,0 +1,26 @@
+package Practice.stopmin;
+
+public class StringPractice {
+
+  public static void main(String[] args) {
+    String a = "Happy"; // 리터럴 방식
+    String b = new String("Java"); // 객체 생성
+
+    System.out.println("a.eqauls(b) = " + a.equals(b));
+
+    boolean c = true; // 프리미티브 -> Null을 담을 수 없다. 대신 string은 안된다!!
+    Boolean e = true; // 레퍼클래스
+
+    e = null;
+
+    int f = 10;
+    Integer g = 10;
+
+    g = null;
+
+    a.equals(b);
+
+    // indexOf
+    // contains
+  }
+}
diff --git a/src/main/java/Problem/stopmin/Chapter3/Q01.java b/src/main/java/Problem/stopmin/Chapter3/Q01.java
index ee0dce3..1246d8b 100644
--- a/src/main/java/Problem/stopmin/Chapter3/Q01.java
+++ b/src/main/java/Problem/stopmin/Chapter3/Q01.java
@@ -10,6 +10,8 @@ public static void main(String[] args) {
     int english = 75;
     int math = 55;
 
-    // TODO: 평균 점수를 구해서 출력하기
+// TODO: 평균 점수를 구해서 출력하기
+    System.out.println((korean + english + math) / 3);
+
   }
 }
diff --git a/src/main/java/Save/Chapter3/Q01.java b/src/main/java/Save/Chapter3/Q01.java
index d6d58e7..9ac77dd 100644
--- a/src/main/java/Save/Chapter3/Q01.java
+++ b/src/main/java/Save/Chapter3/Q01.java
@@ -11,5 +11,6 @@ public static void main(String[] args) {
     int math = 55;
 
     // TODO: 평균 점수를 구해서 출력하기
+    System.out.println((korean + english + math) / 3);
   }
 }
diff --git a/src/main/java/Save/Chapter3/Q03.java b/src/main/java/Save/Chapter3/Q03.java
index ce82b4c..7229646 100644
--- a/src/main/java/Save/Chapter3/Q03.java
+++ b/src/main/java/Save/Chapter3/Q03.java
@@ -9,5 +9,6 @@ public static void main(String[] args) {
     String personNumber = "881120-1068234";
 
     // TODO: 주민등록번호를 연월일(YYYYMMDD) 부분과 그 뒤의 숫자 부분으로 나누어 출력하기
+    System.out.println(personNumber.substring(0, 6) + "\n" + personNumber.substring(8, 14));
   }
 }

From da0b25032b22b6e7853f5db49649db00af11c291 Mon Sep 17 00:00:00 2001
From: stopmin <geemin0@naver.com>
Date: Fri, 7 Jul 2023 22:35:16 +0900
Subject: [PATCH 02/13] solved:Chapter3-2

---
 src/main/java/Problem/stopmin/Chapter3/Q02.java | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/main/java/Problem/stopmin/Chapter3/Q02.java b/src/main/java/Problem/stopmin/Chapter3/Q02.java
index f03f4ff..8f4e9a0 100644
--- a/src/main/java/Problem/stopmin/Chapter3/Q02.java
+++ b/src/main/java/Problem/stopmin/Chapter3/Q02.java
@@ -5,9 +5,21 @@ public class Q02 {
   /**
    * 홀수 짝수 판별
    */
+  public static boolean isOdd(int a) {
+    if (a % 2 == 1) {
+      return true;
+    } else {
+      return false;
+    }
+  }
+
   public static void main(String[] args) {
     int num = 13;
 
-    // TODO: num이 홀수라면 odd를, 짝수라면 even을 출력하기
+    if (isOdd(num)) {
+      System.out.println("Odd");
+    } else {
+      System.out.println("even");
+    }
   }
 }

From cc660708a59a58398e7280d6ce6e22247ac16cb2 Mon Sep 17 00:00:00 2001
From: stopmin <geemin0@naver.com>
Date: Fri, 7 Jul 2023 22:36:31 +0900
Subject: [PATCH 03/13] solved:Chapter3-3

---
 src/main/java/Problem/stopmin/Chapter3/Q03.java | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/main/java/Problem/stopmin/Chapter3/Q03.java b/src/main/java/Problem/stopmin/Chapter3/Q03.java
index c4f33c7..a66578f 100644
--- a/src/main/java/Problem/stopmin/Chapter3/Q03.java
+++ b/src/main/java/Problem/stopmin/Chapter3/Q03.java
@@ -9,5 +9,7 @@ public static void main(String[] args) {
     String personNumber = "881120-1068234";
 
     // TODO: 주민등록번호를 연월일(YYYYMMDD) 부분과 그 뒤의 숫자 부분으로 나누어 출력하기
+    System.out.println(personNumber.substring(0, 6));
+    System.out.println(personNumber.substring(7, 14));
   }
 }

From 6a0d992996ff264af1d442c6a525b08eb3f22a7b Mon Sep 17 00:00:00 2001
From: stopmin <geemin0@naver.com>
Date: Fri, 7 Jul 2023 22:38:34 +0900
Subject: [PATCH 04/13] solved:Chapter3-4

---
 src/main/java/Problem/stopmin/Chapter3/Q05.java | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/main/java/Problem/stopmin/Chapter3/Q05.java b/src/main/java/Problem/stopmin/Chapter3/Q05.java
index 102f88a..0fb8bb7 100644
--- a/src/main/java/Problem/stopmin/Chapter3/Q05.java
+++ b/src/main/java/Problem/stopmin/Chapter3/Q05.java
@@ -9,5 +9,7 @@ public static void main(String[] args) {
     String a = "a:b:c:d";
 
     // TODO: replace 함수를 사용하여 a#b#c#d로 바꿔서 출력해 보자.
+    a = a.replaceAll(":", "#");
+    System.out.println(a);
   }
 }

From f332317dde1f5d917422343089eb8cfd477efe8a Mon Sep 17 00:00:00 2001
From: stopmin <geemin0@naver.com>
Date: Fri, 7 Jul 2023 22:42:12 +0900
Subject: [PATCH 05/13] solved:Chapter3-6

---
 src/main/java/Problem/stopmin/Chapter3/Q06.java | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/main/java/Problem/stopmin/Chapter3/Q06.java b/src/main/java/Problem/stopmin/Chapter3/Q06.java
index 23748ec..af8d5ce 100644
--- a/src/main/java/Problem/stopmin/Chapter3/Q06.java
+++ b/src/main/java/Problem/stopmin/Chapter3/Q06.java
@@ -2,6 +2,8 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
 
 public class Q06 {
 
@@ -13,5 +15,7 @@ public static void main(String[] args) {
     System.out.println(myList); // [1, 3, 5, 4, 2]가 출력됨.
 
     // TODO: 리스트를 [5, 4, 3, 2, 1]로 만들어서 출력하기
+    Collections.sort(myList, Collections.reverseOrder());
+    System.out.println(myList);
   }
 }

From b7eb57f89407b5d071946ab663f07685fed172ad Mon Sep 17 00:00:00 2001
From: stopmin <geemin0@naver.com>
Date: Fri, 7 Jul 2023 22:44:10 +0900
Subject: [PATCH 06/13] solved:Chapter3-7

---
 src/main/java/Problem/stopmin/Chapter3/Q07.java | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/main/java/Problem/stopmin/Chapter3/Q07.java b/src/main/java/Problem/stopmin/Chapter3/Q07.java
index b66f996..02395e5 100644
--- a/src/main/java/Problem/stopmin/Chapter3/Q07.java
+++ b/src/main/java/Problem/stopmin/Chapter3/Q07.java
@@ -13,5 +13,7 @@ public static void main(String[] args) {
     System.out.println(myList); // [Life, is, too, short] 출력됨.
 
     // TODO: 리스트를 "Life is too short" 문자열로 만들어 출력해 보자.
+    String string = String.join(" ", myList);
+    System.out.println(string);
   }
 }

From fb0c8378e8155c4e2f861a5a9d3d7ee6484c8692 Mon Sep 17 00:00:00 2001
From: stopmin <geemin0@naver.com>
Date: Fri, 7 Jul 2023 22:47:35 +0900
Subject: [PATCH 07/13] solved:Chapter3-8

---
 src/main/java/Problem/stopmin/Chapter3/Q08.java | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/main/java/Problem/stopmin/Chapter3/Q08.java b/src/main/java/Problem/stopmin/Chapter3/Q08.java
index e457e8e..6cb3ceb 100644
--- a/src/main/java/Problem/stopmin/Chapter3/Q08.java
+++ b/src/main/java/Problem/stopmin/Chapter3/Q08.java
@@ -1,6 +1,7 @@
 package Problem.stopmin.Chapter3;
 
 import java.util.HashMap;
+import java.util.Map;
 
 public class Q08 {
 
@@ -14,5 +15,7 @@ public static void main(String[] args) {
     grade.put("C", 70);
 
     // TODO: 다음의 맵 grade에서 "B'에 해당되는 값을 추출해 보자. (추출하고 나면 grade에는 "B"에 해당하는 아이템이 사라져야 한다.)
+    grade.remove("B");
+    System.out.println(grade);
   }
 }

From 2a8bb454d9e114b55f0718be292c75c79b8b6fc0 Mon Sep 17 00:00:00 2001
From: stopmin <geemin0@naver.com>
Date: Fri, 7 Jul 2023 22:50:47 +0900
Subject: [PATCH 08/13] solved:Chapter3-9

---
 src/main/java/Problem/stopmin/Chapter3/Q09.java | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/main/java/Problem/stopmin/Chapter3/Q09.java b/src/main/java/Problem/stopmin/Chapter3/Q09.java
index 793f4f2..9523a32 100644
--- a/src/main/java/Problem/stopmin/Chapter3/Q09.java
+++ b/src/main/java/Problem/stopmin/Chapter3/Q09.java
@@ -2,6 +2,7 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.TreeSet;
 
 public class Q09 {
 
@@ -13,5 +14,11 @@ public static void main(String[] args) {
     System.out.println(numbers);  // [1, 1, 1, 2, 2, 3, 3, 3, 4, 4, 5] 출력됨.
 
     // TODO: numbers 리스트에서 중복 숫자를 제거해 보자.
+    TreeSet<Integer> treeSet = new TreeSet<>();
+    for (Integer item : numbers) {
+      treeSet.add(item);
+    }
+
+    System.out.println(treeSet);
   }
 }

From 8907d5018dba0bfd4814c54216592ce75ef48100 Mon Sep 17 00:00:00 2001
From: stopmin <geemin0@naver.com>
Date: Sat, 8 Jul 2023 00:28:34 +0900
Subject: [PATCH 09/13] solved:Chapter3-10

---
 src/main/java/Problem/stopmin/Chapter3/Q10.java | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/main/java/Problem/stopmin/Chapter3/Q10.java b/src/main/java/Problem/stopmin/Chapter3/Q10.java
index 9afb4e7..24c5eb2 100644
--- a/src/main/java/Problem/stopmin/Chapter3/Q10.java
+++ b/src/main/java/Problem/stopmin/Chapter3/Q10.java
@@ -12,8 +12,13 @@ static void printCoffeePrice(int type) {
     priceMap.put(1, 3000);  // 1: 아메리카노
     priceMap.put(2, 4000);  // 2: 아이스 아메리카노
     priceMap.put(3, 5000);  // 3: 카페라떼
-    int price = priceMap.get(type);
-    System.out.println(String.format("가격은 %d원 입니다.", price));
+    Integer price = priceMap.get(type);
+
+    if (price != null) {
+      System.out.println(String.format("가격은 %d원 입니다.", price));
+    } else {
+      System.out.println("해당하는 커피 종류가 없습니다.");
+    }
   }
 
   public static void main(String[] args) {

From 74791069540163805860d17a84608265d1c7b53b Mon Sep 17 00:00:00 2001
From: stopmin <geemin0@naver.com>
Date: Sat, 8 Jul 2023 00:33:40 +0900
Subject: [PATCH 10/13] solved:Chapter4-1

---
 src/main/java/Problem/stopmin/Chapter4/Q02.java | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/main/java/Problem/stopmin/Chapter4/Q02.java b/src/main/java/Problem/stopmin/Chapter4/Q02.java
index a471bc8..1fa306c 100644
--- a/src/main/java/Problem/stopmin/Chapter4/Q02.java
+++ b/src/main/java/Problem/stopmin/Chapter4/Q02.java
@@ -7,5 +7,16 @@ public class Q02 {
    */
   public static void main(String[] args) {
     // TODO: while 문을 사용해서 1부터 1000까지의 자연수 중 3의 배수의 합을 구하기
+    int num = 1;
+    int sum = 0;
+
+    while (num < 1000) {
+      if (num % 3 == 0) {
+        sum += num;
+      }
+      num++;
+    }
+
+    System.out.println(sum);
   }
 }

From 2bb3f15a229aa78b9c5303c618b9f65bf09e4d26 Mon Sep 17 00:00:00 2001
From: stopmin <geemin0@naver.com>
Date: Sat, 8 Jul 2023 00:35:42 +0900
Subject: [PATCH 11/13] solved:Chapter4-3

---
 src/main/java/Problem/stopmin/Chapter4/Q03.java | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/main/java/Problem/stopmin/Chapter4/Q03.java b/src/main/java/Problem/stopmin/Chapter4/Q03.java
index d958601..026279a 100644
--- a/src/main/java/Problem/stopmin/Chapter4/Q03.java
+++ b/src/main/java/Problem/stopmin/Chapter4/Q03.java
@@ -13,5 +13,13 @@ public static void main(String[] args) {
     //***
     //****
     //*****
+    int num = 1;
+    while (num <= 5) {
+      for (int i = 0; i < num; i++) {
+        System.out.print("*");
+      }
+      System.out.print("\n");
+      num++;
+    }
   }
 }

From af00ed9db0d7025596c294ec5c85bb5d381f9d80 Mon Sep 17 00:00:00 2001
From: stopmin <geemin0@naver.com>
Date: Sat, 8 Jul 2023 00:36:27 +0900
Subject: [PATCH 12/13] solved:Chapter4-4

---
 src/main/java/Problem/stopmin/Chapter4/Q04.java | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/main/java/Problem/stopmin/Chapter4/Q04.java b/src/main/java/Problem/stopmin/Chapter4/Q04.java
index 4fa3bbc..5e58082 100644
--- a/src/main/java/Problem/stopmin/Chapter4/Q04.java
+++ b/src/main/java/Problem/stopmin/Chapter4/Q04.java
@@ -7,5 +7,8 @@ public class Q04 {
    */
   public static void main(String[] args) {
     // TODO: for문을 사용해 1부터 100까지의 숫자를 출력해 보자.
+    for (int i = 1; i <= 100; i++) {
+      System.out.println(i);
+    }
   }
 }

From fc0eaa47e09e7c3c622f14e2149190a0e093f00e Mon Sep 17 00:00:00 2001
From: stopmin <geemin0@naver.com>
Date: Sat, 8 Jul 2023 00:38:17 +0900
Subject: [PATCH 13/13] solved:Chapter4-5

---
 src/main/java/Problem/stopmin/Chapter4/Q05.java | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/main/java/Problem/stopmin/Chapter4/Q05.java b/src/main/java/Problem/stopmin/Chapter4/Q05.java
index d3dfaf4..7ad3691 100644
--- a/src/main/java/Problem/stopmin/Chapter4/Q05.java
+++ b/src/main/java/Problem/stopmin/Chapter4/Q05.java
@@ -9,5 +9,11 @@ public static void main(String[] args) {
     int[] marks = {70, 60, 55, 75, 95, 90, 80, 80, 85, 100};
 
     // TODO: for each 문을 사용하여 A 학급의 평균 점수를 구해 보자.
+    int average = 0;
+
+    for (int entry : marks) {
+      average += entry;
+    }
+    System.out.println(average / marks.length);
   }
 }