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@@ -0,0 +1,106 @@
+# 第十一次作业
+
+```java
+//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
+import java.util.Scanner;
+
+public class A1 {
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        System.out.println("请输入r");
+        double num1 = sc.nextInt();
+        System.out.println("圆面积为" + getSum(num1));
+        System.out.println("圆周长为" + getsum(num1));
+
+    }
+
+    public static double getSum(double num1) {
+        double area = 3.14 * num1 * num1;
+        return 3.14 * num1 * num1;
+    }
+
+    public static double getsum(double num1) {
+        double girth = 2 * 3.14 * num1;
+        return 2 * 3.14 * num1;
+    }
+}
+```
+
+``` java
+//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 A2 {
+    public static void main(String[] args) {
+        Scanner sc=new Scanner(System.in);
+        System.out.println("请输入你想查的数");
+        int num= sc.nextInt();
+        Random ran =new Random();
+        int []arr=new int[20];
+        for (int i = 0; i < arr.length; i++) {
+            arr[i]= ran.nextInt(10)+1;
+        }
+        getsum(arr,num);
+        System.out.println(Arrays.toString(arr));
+    }
+    public static void getsum(int[]arr,int num){
+        int count=0;
+        for (int k = 0; k <=10; k++) {
+            if (arr[k]==num){
+                count++;
+            }
+        }
+
+        System.out.println("循环次数为"+count);
+    }
+}
+
+```
+
+``` java
+// 用自定义函数是实现求某数组元素的和（大小不固定）
+import java.util.Scanner;
+
+public class A4 {
+    public static void main(String[] args) {
+        System.out.println("输入元素个数");
+        Scanner sc=new Scanner(System.in);
+        int[] arr=new int[sc.nextInt()];
+        System.out.println("输入"+arr.length+"个数字");
+        for (int i=0;i<arr.length;i++){
+            arr[i]=sc.nextInt();
+        }
+        int result=getsum(arr);
+        System.out.println("它们的和是"+result);
+    }
+    public static int getsum(int[] arr){
+        int count=0;
+        for (int i=0;i<arr.length;i++){
+            count+=arr[i];
+        }
+        return count;
+    }
+}
+
+```
+
+```java
+//用户输入整数n，计算1!+(1!+2!)+(1!+2!+3!)+…..+(1!+2!+…n!)
+import java.util.Scanner;
+
+public class A5 {
+    public static void main(String[] args) {
+        Scanner sc =new Scanner(System.in);
+        System.out.println("输入n为几");
+        int num= sc.nextInt();
+    }
+    public static void getsum(int num){
+        int result=(num*num+num)/2;
+        System.out.println(getsum(int num));
+
+    }
+
+}
+
+```
+
+
+