上传文件至 'w7'

w7/AverageScoreAfter.java

@@ -0,0 +1,33 @@
+package w7;
+
+import java.io.BufferedReader;
+import java.io.FileNotFoundException;
+import java.io.FileReader;
+import java.io.IOException;
+
+public class AverageScoreAfter {
+    public static void main(String[] args) {
+        int sum = 0, count = 0;
+        try (BufferedReader br = new BufferedReader(new FileReader("scores.txt"))) {
+            String line;
+            while ((line = br.readLine()) != null) {
+                line = line.trim();
+                if (line.isEmpty()) continue;
+                try {
+                    sum += Integer.parseInt(line);
+                    count++;
+                } catch (NumberFormatException e) {
+                    System.err.println("忽略无效数字：" + line);
+                }
+            }
+        } catch (FileNotFoundException e) {
+            System.err.println("文件不存在");
+            return;
+        } catch (IOException e) {
+            System.err.println("读取错误");
+            return;
+        }
+        if (count == 0) System.err.println("无有效成绩");
+        else System.out.printf("平均分：%.2f%n", (double) sum / count);
+    }
+}

w7/AverageScoreBefore.java

@@ -0,0 +1,19 @@
+package w7;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+
+public class AverageScoreBefore {
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new FileReader("scores.txt"));
+        String line;
+        int sum = 0, count = 0;
+        while ((line = br.readLine()) != null) {
+            sum += Integer.parseInt(line);
+            count++;
+        }
+        br.close();
+        System.out.println("平均分：" + (double) sum / count);
+    }
+}