diff --git "a/12 \346\236\227\344\277\212\344\274\237/20221220 \347\254\254\345\215\201\344\270\200\346\254\241\344\275\234\344\270\232.md" "b/12 \346\236\227\344\277\212\344\274\237/20221220 \347\254\254\345\215\201\344\270\200\346\254\241\344\275\234\344\270\232.md"
new file mode 100644
index 0000000000000000000000000000000000000000..dd050b2bb2c6c6b2afaeae0a1845c22cfabbd928
--- /dev/null
+++ "b/12 \346\236\227\344\277\212\344\274\237/20221220 \347\254\254\345\215\201\344\270\200\346\254\241\344\275\234\344\270\232.md"	
@@ -0,0 +1,124 @@
+~~~ java
+import java.util.Scanner;
+//2.编写函数，计算圆的面积和周长，在主函数中接受圆的半径，在自定义函数中计算并输出//
+public class zy11 {
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        System.out.println("请输入半径:");
+        int bj = sc.nextInt();
+        System.out.println("圆的周长是："+zc(bj));
+        System.out.println("圆的面积是："+mj(bj));
+    }
+    public static double zc(int bj){
+        //周长公式 2Πr//
+        return 2 * 3.1415926 * bj;
+        }
+        public static double mj(int bj){
+        //面积公式 Π*r2
+        return 3.1415926 * bj * bj;
+        }
+}
+~~~
+
+~~~ java
+import java.util.Arrays;
+import java.util.Random;
+import java.util.Scanner;
+//在主函数中产生20个0-10之间的随机数，将这20个随机数存入数组，并通过函数计算某个数在这些随机数中出现的次数（这“某个数”是在主函数中由用户输入的）
+public class zyd {
+    public static void main(String[] args) {
+        Random r = new Random();
+        int arr [] = new int [10];
+        int count = 0;
+        for (int i = 0; i < arr.length; i++) {
+            int Unknown = r.nextInt(10);
+            arr[i] = Unknown;
+        }
+        System.out.println(Arrays.toString(arr));
+        System.out.println("输入这以上数组里的一个数，查看存在多少次:");
+        Scanner sc = new Scanner(System.in);
+        int num = sc.nextInt();
+        for (int i = 0; i < arr.length; i++) {
+            if (num == arr[i]){
+                count+=1;
+            }
+        }
+        System.out.println("存在"+count+"次");
+    }
+}
+~~~
+
+~~~ java
+import com.sun.org.apache.bcel.internal.generic.SWAP;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Random;
+
+import static java.util.Collections.swap;
+
+public class zydd {
+//在主函数中存入10个数组，在自定义函数中，将该数组最大值与第一个元素交换位置，最小值和最后一个交换位置，然后在主函数中输出交换后的数组
+    public static void main(String[] args) {
+        int []arr=gennerateArray(10, 100);
+        System.out.println("改变前的数组:"+Arrays.toString(arr));
+        int max1 = arr[0];
+        int min = arr[0];
+        for (int i = 0; i < arr.length; i++) {
+            if(max1<arr[i]){
+                max1 = arr[i];
+            }
+            else if(min>arr[i]){
+                min = arr[i];
+            }
+        }
+        for (int j = 0; j < arr.length; j++) {
+            if(arr[j]==max1){
+                arr[j]=arr[0];
+            }
+        }
+        for (int k = 0; k < arr.length; k++) {
+            if(arr[k] == min){
+                arr[k]=arr[arr.length-1];
+            }
+        }
+        arr[0] = max1;
+        arr[arr.length-1] = min;
+        System.out.println("数组:"+Arrays.toString(arr));
+
+    }
+    public static int[]  gennerateArray(int len,int max){
+        int[] arr=new int[len];
+        for(int i=0;i<arr.length;i++){
+            arr[i]=(int)(Math.random()*max);
+        }
+        return arr;
+    }
+}
+~~~
+
+~~~ java
+import java.util.Arrays;
+
+public class zyddd {
+    //用户自定义函数实现求某数组的总和
+    public static void main(String[] args) {
+        int []arr=gennerateArray(10, 100);
+        System.out.println("数组为:"+ Arrays.toString(arr));
+        int sum = 0;
+        for (int i = 0; i < arr.length; i++) {
+            int kemp = arr[i];
+            sum+=kemp;
+        }
+        System.out.println("求和的数组的总和:"+sum);
+
+    }
+    public static int[]  gennerateArray(int len,int max){
+        int[] arr=new int[len];
+        for(int i=0;i<arr.length;i++){
+            arr[i]=(int)(Math.random()*max);
+        }
+        return arr;
+    }
+}
+~~~
diff --git "a/12 \346\236\227\344\277\212\344\274\237/20221223 \347\254\254\345\215\201\344\272\214\346\254\241\344\275\234\344\270\232.md" "b/12 \346\236\227\344\277\212\344\274\237/20221223 \347\254\254\345\215\201\344\272\214\346\254\241\344\275\234\344\270\232.md"
new file mode 100644
index 0000000000000000000000000000000000000000..1dad2344a20ddd6f5c4221203a9abb8792f59bcf
--- /dev/null
+++ "b/12 \346\236\227\344\277\212\344\274\237/20221223 \347\254\254\345\215\201\344\272\214\346\254\241\344\275\234\344\270\232.md"	
@@ -0,0 +1,96 @@
+~~~ java
+import java.util.Scanner;
+//书本管理系统.12月23日作业
+public class zy12 {
+    public static void main(String[] args) {
+        String[] students = new String[10];
+        //录入书名
+        students[0]="<钢铁是怎样炼成的>";
+        students[1]="<三国演义>";
+        students[2]="<西游记>";
+        start();
+        int num = choice();
+        todo(num,students);
+    }
+    //启动菜单
+    public static void start(){
+        System.out.println(""+
+                "===================\n"+
+                "2班书本管理系统\n"+
+                "\t\t1.浏览书本\t\t-\n"+
+                "\t\t2.添加书本\t\t-\n"+
+                "\t\t3.修改书本\t\t-\n"+
+                "\t\t4.删除书本\t\t-\n"+
+                "\t\t5.查询书本\t\t-\n"+
+                "\t\t6.退出\t\t-\n");
+    }
+    //选择操作
+    public static int choice(){
+        System.out.println("请选择您的操作:");
+        Scanner sc = new Scanner(System.in);
+        int num = sc.nextInt();
+        return num;
+    }
+    public static void todo(int num,String[] students){
+        switch (num){
+            case 1:
+                System.out.println("1.浏览所有图书");
+                viewBook(students);
+            break;
+            case 2:
+                System.out.println("2.添加书本");
+                addStoudent(students);
+                break;
+            case 3:
+                System.out.println("3.修改书本");
+                editStudent(students);
+                break;
+            default:
+                System.out.println("无");
+        }
+    }
+    public static void viewBook(String[] students){
+         for (String name:students){
+             System.out.print(name+"\t");
+         }
+    }
+    //添加书本
+    public static void addStoudent(String[] students){
+        System.out.println("请输入要添加的书");
+        Scanner sc = new Scanner(System.in);
+        String name = sc.next();
+        int index = -1;
+        for (int i=0; i< students.length;i++){
+            if (students[i]==null){
+                index =i;
+            }
+        }
+        students[index] = name;
+        System.out.println("添加成功");
+    }
+    //修改书名
+    public static void editStudent(String[] students){
+        System.out.println("请输入需要修改的书");
+        Scanner sc = new Scanner(System.in);
+        String name = sc.next();
+        int index = -1;
+        for (int i=0; i< students.length;i++){
+            if (name.equals((students[i]))){
+                index =i;
+                break;
+            }
+        }
+        System.out.println(index);
+        if (index ==-1){
+            System.out.println("没有这本书");
+        }else {
+            System.out.println("请重新输入");
+            String newName = sc.next();
+            students[index]=newName;
+            System.out.println("修改成功");
+        }
+    }
+}
+
+~~~
+