diff --git "a/\346\226\271\346\263\225\345\244\215\344\271\2402/\346\235\250\345\270\206/Demo01.java" "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\346\235\250\345\270\206/Demo01.java"
new file mode 100644
index 0000000000000000000000000000000000000000..80802b1bb04c2cb56b9dcd366fcbf6e33e45b721
--- /dev/null
+++ "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\346\235\250\345\270\206/Demo01.java"
@@ -0,0 +1,43 @@
+package a;
+
+import java.util.Random;
+
+public class Demo01 {
+
+	public static void main(String[] args) {
+		
+		Random abc = new Random();
+		
+		int [] arr = new int [4]; 
+		int [] arr1 = new int [3];
+		
+		for (int i = 0; i < arr.length; i++) {
+			arr[i] = abc.nextInt(9)+1;
+		}
+		print(arr);
+		for (int i = 0; i < arr1.length; i++) {
+			arr1[i] = abc.nextInt(9)+1;
+		}
+		print1(arr1);
+		
+		
+	}	
+	
+	public static void print (int []arr) {
+		System.out.print("[");
+		for (int i = 0; i < arr.length; i++) {
+				System.out.print(arr[i]);	
+		}
+		System.out.print(" ");
+	}
+	
+	public static void print1 (int []arr1) {
+		for (int i = 0; i < arr1.length; i++) {
+				System.out.print(arr1[i]);
+			
+		}
+		System.out.print("]");
+		
+	}
+	
+}
diff --git "a/\346\226\271\346\263\225\345\244\215\344\271\2402/\346\235\250\345\270\206/Demo02.java" "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\346\235\250\345\270\206/Demo02.java"
new file mode 100644
index 0000000000000000000000000000000000000000..415ffcd81e1c999bf39cd4221a2a6491fbf59334
--- /dev/null
+++ "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\346\235\250\345\270\206/Demo02.java"
@@ -0,0 +1,22 @@
+
+public class Demo02 {
+
+	public static void main(String[] args) {
+		
+		int a = 10;
+		int b = 20;
+		int c;
+		System.out.println("交换前：");
+		System.out.println("a:"+a);
+		System.out.println("B:"+b);
+		
+		c = a;
+		a = b;
+		b = c;
+		
+		System.out.println("交换后：");
+		System.out.println("a:"+a);
+		System.out.println("B:"+b);
+	}
+
+}
diff --git "a/\346\226\271\346\263\225\345\244\215\344\271\2402/\346\235\250\345\270\206/Demo03.java" "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\346\235\250\345\270\206/Demo03.java"
new file mode 100644
index 0000000000000000000000000000000000000000..614764f234f6c0f295c3f3a168702f49c750320e
--- /dev/null
+++ "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\346\235\250\345\270\206/Demo03.java"
@@ -0,0 +1,48 @@
+import java.util.Random;
+
+public class Demo03 {
+
+	public static void main(String[] args) {
+		
+		Random abc = new Random();
+		
+//		int [] arr = {50,35,95,43,2};
+		int [] arr = new int [6];
+		for (int i = 0; i < arr.length; i++) {
+			arr[i] = abc.nextInt(100)+1;
+		}
+		
+		System.out.println("排序前：");
+		print(arr);
+		
+		System.out.println("排序后：");
+		print(desc(arr));
+	}
+	
+	public static int[] desc (int arr []){
+		int num;
+		for (int i = 0; i < arr.length-1; i++) {
+			for (int j = 0; j < arr.length-1-i; j++) {
+				if(arr[j] < arr[j+1]) {
+					num = arr[j];
+					arr[j] = arr[j+1];
+					arr[j+1] = num;
+				}
+			}
+		}
+		
+		return arr;
+	}
+	
+	public static void print(int []arr) {
+		System.out.print("[");
+		for (int i = 0; i < arr.length; i++) {
+			if (i == arr.length-1) {
+				System.out.print(arr[i]);
+			}else {
+				System.out.print(arr[i]+",");
+			}
+		}
+		System.out.println("]");
+	}
+}
diff --git "a/\346\226\271\346\263\225\345\244\215\344\271\2402/\346\235\250\345\270\206/Demo04.java" "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\346\235\250\345\270\206/Demo04.java"
new file mode 100644
index 0000000000000000000000000000000000000000..244399150e0b2daf7eead25b443383f84b49933c
--- /dev/null
+++ "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\346\235\250\345\270\206/Demo04.java"
@@ -0,0 +1,51 @@
+
+public class Demo04 {
+
+	public static void main(String[] args) {
+
+		int [] arr = {19, 28, 37, 46, 50};
+		
+		System.out.println("交换前：");
+		System.out.print("[");
+		for (int i = 0; i < arr.length; i++) {
+			if (i == arr.length-1) {
+				System.out.print(arr[i]);
+			}else {
+				System.out.print(arr[i]+",");
+				
+			}
+		}
+		System.out.println("]");
+		
+		
+		abc(arr);
+		System.out.println("交换后：");
+		System.out.print("[");
+		for (int i = 0; i < arr.length; i++) {
+			
+			if (i == arr.length-1) {
+				System.out.print(arr[i]);
+			}else {
+				System.out.print(arr[i]+",");
+				
+			}
+		}
+		System.out.println("]");
+
+	}
+	
+	public static int [] abc (int [] arr){
+		int a = 0;
+		int b = arr.length-1;
+		int num;
+		
+		for (; a<b; a++,b--) {
+			num = arr[b];
+			arr[b] = arr[a];
+			arr[a] = num;
+		}
+		
+		return arr;
+	}
+
+}