From 2b8c4f2c8711b2eaf66fb85eea0c8c577dbdad43 Mon Sep 17 00:00:00 2001
From: haerong22 <haerong22@naver.com>
Date: Sat, 6 Mar 2021 20:07:55 +0900
Subject: [PATCH] java oop : variable vs array

---
 JavaOOP/src/Java04.java | 32 ++++++++++++++++++++++++++++++++
 JavaOOP/src/Java05.java | 40 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+)
 create mode 100644 JavaOOP/src/Java04.java
 create mode 100644 JavaOOP/src/Java05.java

diff --git a/JavaOOP/src/Java04.java b/JavaOOP/src/Java04.java
new file mode 100644
index 00000000..e1b2d6ff
--- /dev/null
+++ b/JavaOOP/src/Java04.java
@@ -0,0 +1,32 @@
+public class Java04 {
+
+    public static void main(String[] args) {
+        // 변수 VS 배열
+        int a = 10, b = 20, c = 30;
+
+        // a + b + c = ?  메소드 처리 -> hap()
+        hap(a, b, c);
+
+        int[] arr = new int[3];
+        arr[0] = 10;
+        arr[1] = 20;
+        arr[2] = 30;
+
+        hap(arr);
+    }
+
+    // 하나의 값마다 파라미터로 받아야함 -> 데이터 이동이 불편
+    public static void hap(int a, int b, int c) {
+        int sum = a + b + c;
+        System.out.println(sum);
+    }
+
+    // 여러 값을 배열로 한번에 이동
+    public static void hap(int[] arr) {
+        int sum = 0;
+        for (int i : arr) {
+            sum += i;
+        }
+        System.out.println(sum);
+    }
+}
diff --git a/JavaOOP/src/Java05.java b/JavaOOP/src/Java05.java
new file mode 100644
index 00000000..eb8a3ee1
--- /dev/null
+++ b/JavaOOP/src/Java05.java
@@ -0,0 +1,40 @@
+public class Java05 {
+    public static void main(String[] args) {
+        // 2차원 배열
+        int[][] a = new int[3][3];
+        a[0][0] = 1;
+        a[0][1] = 2;
+        a[0][2] = 3;
+
+        a[1][0] = 1;
+        a[1][1] = 2;
+        a[1][2] = 3;
+
+        a[2][0] = 1;
+        a[2][1] = 2;
+        a[2][2] = 3;
+
+        for (int i = 0; i < a.length ; i++) {
+            for (int j = 0; j < a[i].length; j++) {
+                System.out.print(a[i][j] + "\t");
+            }
+            System.out.println();
+        }
+
+        // 가변길이 배열
+        int[][] star = new int[5][];
+        star[0] = new int[1];
+        star[1] = new int[2];
+        star[2] = new int[3];
+        star[3] = new int[4];
+        star[4] = new int[5];
+
+        for (int i = 0; i <star.length ; i++) {
+            for (int j = 0; j < star[i].length ; j++) {
+                star[i][j] = '*';
+                System.out.print((char) star[i][j]);
+            }
+            System.out.println();
+        }
+    }
+}