diff --git a/.classpath b/.classpath
index 51a8bba..46bbddf 100644
--- a/.classpath
+++ b/.classpath
@@ -1,6 +1,6 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<classpath>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8"/>
-	<classpathentry kind="src" path="src"/>
-	<classpathentry kind="output" path="bin"/>
-</classpath>
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/jre1.8.0_191"/>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>
diff --git a/src/practice02/Prob01.java b/src/practice02/Prob01.java
index 8dbc760..5287c98 100644
--- a/src/practice02/Prob01.java
+++ b/src/practice02/Prob01.java
@@ -1,9 +1,31 @@
 package practice02;
 
+import java.util.Scanner;
+
 public class Prob01 {
 
 	public static void main(String[] args) {
 		final int[] MONEYS = { 50000, 10000, 5000, 1000, 500, 100, 50, 10, 5, 1 };
+		int d = 0;
+		Scanner scanner = new Scanner( System.in );
+		System.out.println("금액:");
+		int num = scanner.nextInt();  
+		
+		for(int i =0;i<10;i++)
+		{
+			d = num / MONEYS[i];
+			System.out.println(MONEYS[i]+"원 :"+d+"개" );
+			d = num % MONEYS[i];
+			
+			num = d;
+			
+		}
+		 
+		
+		
+		
+	
+		scanner.close();
 	}
 
 }
diff --git a/src/practice02/Prob02.java b/src/practice02/Prob02.java
index 83548be..c63968e 100644
--- a/src/practice02/Prob02.java
+++ b/src/practice02/Prob02.java
@@ -1,8 +1,31 @@
 package practice02;
+import java.util.Scanner;
 
 public class Prob02 {
 
-	public static void main(String[] args) {
+	public static void main(String[] args) {		
+		Scanner in = new Scanner( System.in );
+        int intArray[] = new int[5];
+        double sum = 0;
+        
+        System.out.println("5개의 숫자를 입력하시오.");
+        
+        for(int i = 0;i<5;i++)
+        {
+        	intArray[i] = in.nextInt();
+        }
+        
+        for(int i =0; i<5;i++)
+        {
+          sum = intArray[i] + sum;
+        }
+        
+        System.out.println("평균은"+ sum/5+" 입니다.");
+        
+        
+        
+        in.close();
+		
 	}
 
 }
diff --git a/src/practice02/Prob03.java b/src/practice02/Prob03.java
index c56a9e4..8583790 100644
--- a/src/practice02/Prob03.java
+++ b/src/practice02/Prob03.java
@@ -1,6 +1,29 @@
 package practice02;
-
 public class Prob03 {
+	
+	
+	public static void printCharArray(char[] c) {
+		
+		System.out.println(c);
+		
+
+	}
+
+	public static void replaceSpace(char[] c) {	
+		
+		for(int i =0 ; i<c.length;i++)
+		{
+			
+			if(c[i]==' ')
+			{
+				c[i]=',';
+				
+			}
+			
+	}
+		
+		
+	}
 
 	public static void main(String args[]) {
 		char c[] = { 'T', 'h', 'i', 's', ' ', 'i', 's', ' ', 'a', ' ', 'p', 'e', 'n', 'c', 'i', 'l', '.' };
@@ -15,4 +38,5 @@ public static void main(String args[]) {
 		printCharArray(c);
 	}
 	
+	
 }
diff --git a/src/practice02/Prob04.java b/src/practice02/Prob04.java
index 4e36d34..121f6fa 100644
--- a/src/practice02/Prob04.java
+++ b/src/practice02/Prob04.java
@@ -4,6 +4,7 @@ public class Prob04 {
 
 	public static void main(String[] args) {
 		char[] c1 = reverse( "Hello World" );
+		
 		printCharArray( c1 );
 		
 		char[] c2 = reverse( "Java Programming!" );
@@ -11,10 +12,23 @@ public static void main(String[] args) {
 	}
 	
 	public static char[] reverse(String str) {
-		/* 코드를 완성합니다 */
+		
+		char[] c1 = str.toCharArray();
+		int left  = 0;             
+	    int right = c1.length - 1;  
+
+	    while (left < right) {
+	      char temp = c1[left];
+	      c1[left]  = c1[right];    
+	      c1[right] = temp;
+
+	      left++; right--;        
+	    }
+		
+		return c1;
 	}
 
 	public static void printCharArray(char[] array){
-		/* 코드를 완성합니다 */
+		System.out.println(array);
 	}
 }
diff --git a/src/practice02/Prob05.java b/src/practice02/Prob05.java
index 0e54b0f..fcee4e7 100644
--- a/src/practice02/Prob05.java
+++ b/src/practice02/Prob05.java
@@ -1,10 +1,50 @@
 package practice02;
 
+import java.util.Random;
+import java.util.Scanner;
+
 public class Prob05 {
 
 
 	public static void main(String[] args) {
-
+		
+		while(true) {
+		Scanner scanner = new Scanner( System.in );
+		Random r = new Random();
+		int k = r.nextInt(100) + 1;
+		int start = 1;
+		int end = 100;
+		System.out.println(k);
+		while(true)
+		{
+		int num = scanner.nextInt();  
+		if(num<k)
+		{
+			start = num;
+			System.out.println("더높게"+start+"-"+end);
+		}
+		else if(num>k)
+		{
+			end = num;
+			System.out.println("더낮게"+start+"-"+end);
+		}
+		else if(num==k)
+		{
+			System.out.println("정답");
+			System.out.println("종료하시겠습니까? y/n");
+			String answer = scanner.next();
+			if( answer.equals("y") ){
+				end = 0;
+				break;
+			    //종료하도록 작성한다.	
+			}	
+		}
+		
+		}
+		
+		if(end==0)
+			break;
+		scanner.close();
 	}
-
 }
+	}