diff --git "a/\346\226\271\346\263\225\345\244\215\344\271\2402/\345\220\264\344\276\235\346\266\265/JiaoHuan.java" "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\345\220\264\344\276\235\346\266\265/JiaoHuan.java"
new file mode 100644
index 0000000000000000000000000000000000000000..ae2e9d395b5322a5a449796be48c7ac706cebd52
--- /dev/null
+++ "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\345\220\264\344\276\235\346\266\265/JiaoHuan.java"
@@ -0,0 +1,17 @@
+package 第三次课作业;
+//已知两个整数变量a = 10，b = 20，使用程序实现这两个变量的数据交换
+//​        最终输出a = 20，b = 10;
+public class JiaoHuan {
+
+	public static void main(String[] args) {
+    int a = 10;
+    int b = 20;
+    int num ;
+    num = a;
+    a = b;
+    b = num;
+    System.out.println("输出前:a=10,b=20");   
+    System.out.println("输出后:"+"a="+a+","+"b="+b+";");
+	}
+
+}
\ No newline at end of file
diff --git "a/\346\226\271\346\263\225\345\244\215\344\271\2402/\345\220\264\344\276\235\346\266\265/JiaoHuan2.java" "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\345\220\264\344\276\235\346\266\265/JiaoHuan2.java"
new file mode 100644
index 0000000000000000000000000000000000000000..d3dd4cb655b6611a896e9617d8f11899be3100c2
--- /dev/null
+++ "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\345\220\264\344\276\235\346\266\265/JiaoHuan2.java"
@@ -0,0 +1,35 @@
+package 第三次课作业;
+//定义一个方法，用来实现如下功能：
+//​ 已知一个数组 arr = {19, 28, 37, 46, 50}; 用程序实现把数组中的元素值交换，
+//​ 交换后的数组 arr = {50, 46, 37, 28, 19}; 并在控制台输出交换后的数组元素
+public class JiaoHuan2 {
+    
+	public static void main(String[] args) {
+	    int	[] a = new int [] {19,28,37,46,50};
+	    
+	        System.out.println("交换前:");
+	    for (int i = 0; i < a.length; i++) {
+			System.out.print(a[i]+",");
+		}
+        
+        int c [] = new int [5];
+        c=b(a);        
+        System.out.println();
+        System.out.println("交换后:");
+             
+        for (int i = 0; i < c.length; i++) {
+			System.out.print(c[i]+",");			
+		}     
+	}
+	
+    public static int [] b (int [] a){
+    	int num ;
+    	for (int i = 0; i < a.length/2; i++) {
+			  num= a[i];
+			  a[i]=a[a.length-1-i]; 
+			  a[a.length-1-i]=num;
+		}   	
+    	return a;
+    }
+}
+
diff --git "a/\346\226\271\346\263\225\345\244\215\344\271\2402/\345\220\264\344\276\235\346\266\265/PaiXu.java" "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\345\220\264\344\276\235\346\266\265/PaiXu.java"
new file mode 100644
index 0000000000000000000000000000000000000000..7881cd425e76ca965fbd1c2c42bb136111259189
--- /dev/null
+++ "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\345\220\264\344\276\235\346\266\265/PaiXu.java"
@@ -0,0 +1,35 @@
+package �����ο���ҵ;
+//�÷���ʵ�����������
+//����һ��������ʵ������Ӵ�С���򣬴���һ���������飬����һ���Ӵ�С���������
+public class PaiXu {
+
+	public static void main(String[] args) {
+       int [] a = new int [] {22,19,80,57,20,66};
+       
+        System.out.println("����ǰ:");
+       for (int i = 0; i < a.length; i++) {		
+    	System.out.print(a[i]+","); 
+	}
+              
+       int [] b = b(a);
+        System.out.println();
+        System.out.println("�����:");
+       for (int i = 0; i < b.length; i++) {    	
+		System.out.print(b[i]+",");
+	}
+	}	
+	
+    public static int [] b (int [] a) {
+		int num ; 
+		for (int i = 0; i < a.length-1; i++) {
+			for (int j = 0; j < a.length-1-i; j++) {
+			if (a[j]<a[j+1]) {
+				num=a[j];
+				a[j]=a[j+1];
+				a[j+1]=num;
+			}
+		}					
+		}
+		return a;
+	}
+}
diff --git "a/\346\226\271\346\263\225\345\244\215\344\271\2402/\345\220\264\344\276\235\346\266\265/SuiJiShengCheng.java" "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\345\220\264\344\276\235\346\266\265/SuiJiShengCheng.java"
new file mode 100644
index 0000000000000000000000000000000000000000..95d6f213bde19936078860b5d5875ce422b6f580
--- /dev/null
+++ "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\345\220\264\344\276\235\346\266\265/SuiJiShengCheng.java"
@@ -0,0 +1,18 @@
+package �����ο���ҵ;
+//����һ��������ʵ�ֵĹ����ǣ�����������п���7λ�������ص����ݸ�ʽ�磺0586 756
+//Random
+//����
+//�ַ�����ȡ
+public class SuiJiShengCheng {
+
+	public static void main(String[] args) {
+		String a="0586759";
+		System.out.println("����������п���7λ��Ϊ:");
+		System.out.println( b(a));       
+	}
+	
+	public static String b(String a) {			
+		String e=a.substring(0,4)+" "+a.substring(4,7);
+		return e;
+	} 
+}