1.测试如下程序段： main() { int i=1;n1=n2=0; float sum=0; float average; float score[100]; while(score[i]!=-1&&n2<50) { n2=n2+1; if(score[i]>0&&score[i]<100) { n1=n1+1; sum=sum+score[i]; } i=i+1; } if(n1>0) average=sum/n1; else average=-1; printf(“n1=%d,sum=%f,average=%f\n”,n1,sum,average); } 要求：①画出这段代码的程序流程图和控制流程图；②计算环路复杂度；③列出独立路径；④设计测试用例。

1. 程序流程图如下：

+--------------+
| 初始化 i, n1, |
|   n2, sum    |
+--------------+
       |
       v
+--------------+
| 初始化 average|
+--------------+
       |
       v
+--------------+       +----------------+
| 初始化 score |       | score[i] != -1 |
+--------------+       |     && n2 < 50  |
       |                +----------------+
       v                        |
+--------------+                |
|   while循环   |                |
+--------------+                |
       |                        |
       v                        v
+--------------+       +----------------+
|     判断     |       | score[i] > 0 && |
|   score[i]   |-----> | score[i] < 100  |
|     是否     |       +----------------+
|    合法      |                |
+--------------+                v
       |               +----------------+
       v               |   n1 = n1 + 1   |
+--------------+       +----------------+
|   计算总和   |                |
+--------------+                |
       |                        v
       v               +----------------+
+--------------+       |   sum = sum +   |
|   计算平均值  |-----> |    score[i]    |
+--------------+       +----------------+
       |                        |
       v                        v
+--------------+       +----------------+
|   判断是否有  |       | i = i + 1      |
|    合法数据  |       +----------------+
+--------------+                |
       |                        v
       v               +----------------+
+--------------+       |     循环结束   |
|   计算平均值  |       +----------------+
+--------------+                |
       |                        v
       v               +----------------+
+--------------+       |   计算 average  |
|    打印结果   |       +----------------+
+--------------+

2. 控制流程图如下：

+--------+          +---------+
|  开始  |----------> 初始化 |
+--------+          +---------+
    |                     |
    v                     |
+--------------+         |
| 初始化 average|         |
+--------------+         |
    |                     |
    v                     |
+--------------+         |
| 初始化 score |         |
+--------------+         |
    |                     |
    v                     |
+--------------+         |
|   while循环   |         |
+--------------+         |
    |                     |
    v                     |
+--------------+         |
|     判断     |         |
+--------------+         |
    |                     |
    v                     |
+--------------+         |
|   计算总和   |         |
+--------------+         |
    |                     |
    v                     |
+--------------+         |
|   计算平均值  |         |
+--------------+         |
    |                     |
    v                     |
+--------------+         |
|    打印结果   |         |
+--------------+         |
    |                     |
    v                     |
+--------+          +---------+
|  结束  |<---------| 退出程序|
+--------+          +---------+

3. 环路复杂度为 6。

4. 独立路径：

- 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 9 → 10 → 11 → 12 → 13 → 14 → 15 → 16 → 17 → 18
- 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 9 → 10 → 11 → 12 → 13 → 14 → 16 → 17 → 18
- 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 9 → 10 → 11 → 12 → 13 → 14 → 16 → 15 → 10 → 11 → 12 → 13 → 14 → 15 → 16 → 17 → 18
- 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 9 → 10 → 11 → 12 → 13 → 14 → 16 → 15 → 10 → 11 → 12 → 13 → 14 → 16 → 17 → 18

注：路径中的数字表示程序流程图中的节点编号。

5. 设计测试用例：

- 测试用例1：

输入：score = {-1}
输出：n1 = 0, sum = 0.000000, average = -1.000000

- 测试用例2：

输入：score = {101}
输出：n1 = 0, sum = 0.000000, average = -1.000000

- 测试用例3：

输入：score = {80, 90, 95, 85, -1}
输出：n1 = 4, sum = 350.000000, average = 87.500000

- 测试用例4：

输入：score = {80, 90, 95, 101, -1}
输出：n1 = 3, sum = 265.000000, average = 88.333336

- 测试用例5：

输入：score = {80, 90, 95, 85, 90, 80, 70, 60, 50, 40, 30, 20, 10, 0, -1}
输出：n1 = 8, sum = 550.000000, average = 68.750000