CHOCOCHANEL's GodOfJava Study Logs

Chapter01/src/Calculator.java

@@ -1,27 +1,28 @@
 public class Calculator {
-
+
+	public int sum = 0;
+	public int result;
+
 	public int add(int num1, int num2) {
-		int sum;
 		sum = num1 + num2;
 		return sum;
 	}
 
 	public int addAll(int num1, int num2, int num3) {
-		int sum=0;
-		// Insert code here.
+		sum = num1 + num2 + num3;
 		return sum;
 	}
 
 	public int subtract(int num1, int num2) {
-		int result=num1 - num2;
+		result = num1 - num2;
 		return result;
 	}
 	public int multiply(int num1, int num2) {
-		int result=num1 * num2;
+		result = num1 * num2;
 		return result;
 	}
 	public int divide(int num1, int num2) {
-		int result=num1 / num2;
+		result = num1 / num2;
 		return result;
 	}
 

Chapter01/src/MyCalculator.java

@@ -0,0 +1,30 @@
+public class MyCalculator {
+
+    public int add(int a, int b) {
+        System.out.printf("%d + %d = %d", a, b, a + b);
+        System.out.println();
+        return a + b;
+    }
+
+    public int subtract(int a, int b) {
+        System.out.printf("%d - %d = %d", a, b, a - b);
+        System.out.println();
+        return a - b;
+    }
+
+    public int multiply(int a, int b) {
+        System.out.printf("%d * %d = %d", a, b, a * b);
+        System.out.println();
+        return a * b;
+    }
+
+    public int divide(int a, int b) {
+        if (b == 0) {
+            System.out.println("Error: Divided By Zero");
+            return -1; // unexpected error
+        }
+        System.out.printf("%d / %d = %d", a, b, a / b);
+        System.out.println();
+        return a / b;
+    }
+}

Chapter01/src/MyCalculatorImpl.java

@@ -0,0 +1,60 @@
+import java.util.Scanner;
+
+public class MyCalculatorImpl {
+
+    public static void showMenu() {
+        System.out.println("======= Menu =======");
+        System.out.println("0. Exit");
+        System.out.println("1. Add");
+        System.out.println("2. Subtract");
+        System.out.println("3. Multiply");
+        System.out.println("4. Divide");
+        System.out.println("Please put the command number:");
+    }
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        MyCalculator myCalculator = new MyCalculator();
+        boolean flag = true;
+        int command = 0;
+        int a = 0;
+        int b = 0;
+        while (flag) {
+            showMenu();
+            command = sc.nextInt();
+            switch (command) {
+                case 0:
+                    flag = false;
+                    System.out.println("Thanks. See you later :)");
+                    break;
+                case 1:
+                    System.out.println("Put a, b that you want to add: ");
+                    a = sc.nextInt();
+                    b = sc.nextInt();
+                    myCalculator.add(a, b);
+                    break;
+                case 2:
+                    System.out.println("Put a, b that you want to subtract: ");
+                    a = sc.nextInt();
+                    b = sc.nextInt();
+                    myCalculator.subtract(a, b);
+                    break;
+                case 3:
+                    System.out.println("Put a, b that you want to multiply: ");
+                    a = sc.nextInt();
+                    b = sc.nextInt();
+                    myCalculator.multiply(a, b);
+                    break;
+                case 4:
+                    System.out.println("Put a, b that you want to divide: ");
+                    a = sc.nextInt();
+                    b = sc.nextInt();
+                    myCalculator.divide(a, b);
+                    break;
+                default:
+                    System.out.println("You got an wrong number. Please try again.");
+                    break;
+            }
+        }
+    }
+}

Chapter02/src/MyProfile.java

@@ -0,0 +1,41 @@
+public class MyProfile {
+    private String name = "";
+    private int age = -1;
+
+    public MyProfile(String name) {
+        this.name = name;
+    }
+
+    public MyProfile(int age) {
+        this.age = age;
+    }
+
+    public MyProfile(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    @Override
+    public String toString() {
+        return "MyProfile{" +
+                "name='" + name + '\'' +
+                ", age=" + age +
+                '}';
+    }
+}

Chapter02/src/MyProfileImpl.java

@@ -0,0 +1,6 @@
+public class MyProfileImpl {
+    public static void main(String[] args) {
+        MyProfile profile = new MyProfile("choco-chanel", 25);
+        System.out.println(profile);
+    }
+}

Chapter03/src/MyProfile.java

@@ -0,0 +1,28 @@
+public class MyProfile {
+    String name = "default";
+    int age = 0;
+
+    public static void main(String[] args) {
+        Profile profile = new Profile();
+        profile.setName("choco-chanel");
+        profile.setAge(25);
+        profile.printName();
+        profile.printAge();
+    }
+
+    public void setName(String str) {
+        name = str;
+    }
+
+    public void setAge(int value) {
+        age = value;
+    }
+
+    public void printName() {
+        System.out.println("My name is " + name);
+    }
+
+    public void printAge() {
+        System.out.println("My age is " + age);
+    }
+}

Chapter04/src/JavaVariables.java

@@ -0,0 +1,16 @@
+public class JavaVariables {
+    private int instanceVariable;
+
+    private static int classVariable;
+
+    public void method(String[] parameters) {
+        int localVariable = this.instanceVariable;
+    }
+
+    public static void main(String[] args) {
+        System.out.println("Java의 변수는 총 4가지가 있다.");
+        System.out.println("1) 클래스 변수 vs 2) 인스턴스 변수");
+        System.out.println("3) Parameter vs 4) 지역 변수");
+        System.out.println("각 변수는 생명주기와 용도가 다르다");
+    }
+}

README.md

@@ -1,14 +1,58 @@
-# GodOfJava 2nd Edition
-자바의신 코드 저장소 입니다.
+### CHOCO-CHANEL'S JAVA STUDY LOGS
+##### Reference 
+```python
+# Fork: GodOfJava 2nd Edition
+# 자바의신 코드 저장소
+```
 
-# 예제 실행기 다운로드
-상단의 메뉴에서 "Release" 를 클릭하면 파일을 다운로드 할 수 있습니다.
+##### Logs
+* 01 Programming
+> Class & Method <br>
+> - A class is the minimum unit of java consisting of state and behavior. 
+> - A method receives the parameter and returns the calculation result. <br>
 
-# 연습문제 답
-연습문제의 답은 각 챕터의 링크를 따라가면 확인할 수 있습니다.
-예) Chapter01/src 디렉터리로 이동하면 Calculator.java 파일의 소스를 보실 수 있습니다.
+* 02 Hello God Of Java
+ > Building a development Environment
+ > - Compilation of Java File <br>
+ > - Printing on the console <br>
+ > - Comment <br>
+```java
+public class Sample {
+    public static void main(String[] args){
+        System.out.println("Printing on the console.");
+    }
+}
+```
 
-# 질문은 자바의 신 카페에~~~
-질문은 자바의 신 카페에서 해 주시기 바랍니다.
+* 03 Object Oriented Programming
+> Concept of Object
+> - An object is an instance of a class. <br>
+> - A class consists of variables and methods. <br>
+```java
+public class Calculator {
+    public static void main(String[] args) {
+        System.out.println("Constructor");
+        Calculator myCalculator = new Calculator();
+    }
+}
+```
 
-http://cafe.naver.com/godofjava.cafe
+* 04 Data Type
+> Variables of Java
+> - Java has 4 types of variables and each of them has different range of scope and usability. <br>
+```python
+# === 4 Types of Variables ===
+1. Local variables
+2. Parameters
+3. Instance Variables
+4. Class Variables
+```
+> Data Types
+> - Primitive Data Type vs Reference Data Type
+```python
+# === 4 Types of Variables ===
+1. Local variables
+2. Parameters
+3. Instance Variables
+4. Class Variables
+```