diff --git a/s-day04/src/com/inmind/sort05/SortDemo12.java b/s-day04/src/com/inmind/sort05/SortDemo12.java
new file mode 100644
index 0000000..7b97f8f
--- /dev/null
+++ b/s-day04/src/com/inmind/sort05/SortDemo12.java
@@ -0,0 +1,27 @@
+package com.inmind.sort05;
+
+import java.util.Arrays;
+
+/*
+冒泡排序
+ */
+public class SortDemo12 {
+    public static void main(String[] args) {
+        //创建一个数组
+        int[] arr = {1, 5, 3, 4, 2};
+        //5个数字，要排4趟
+        for (int i = 0; i < arr.length - 1; i++) {//循环4次
+            //每趟排序的次数刚好就是arr.length - 1-i
+            for (int j = 0; j < arr.length - 1 - i; j++) {
+                //每趟中每次都是相邻比较,如果大或者小就往后（升序，降序）
+                if (arr[j] < arr[j + 1]) {
+                    //交换
+                    int temp = arr[j];
+                    arr[j] = arr[j + 1];
+                    arr[j+1] = temp;
+                }
+            }
+        }
+        System.out.println(Arrays.toString(arr));
+    }
+}