tasks a-s

Task/Read-a-specific-line-from-a-file/Java/read-a-specific-line-from-a-file.java

@@ -0,0 +1,33 @@
+package linenbr7;
+
+import java.io.*;
+
+public class LineNbr7 {
+
+    public static void main(String[] args) throws Exception {
+        File f = new File(args[0]);
+        if (!f.isFile() || !f.canRead())
+            throw new IOException("can't read " + args[0]);
+
+        BufferedReader br = new BufferedReader(new FileReader(f));
+        try (LineNumberReader lnr = new LineNumberReader(br)) {
+            String line = null;
+            int lnum = 0;
+            while ((line = lnr.readLine()) != null
+                    && (lnum = lnr.getLineNumber()) < 7) {
+            }
+
+            switch (lnum) {
+                case 0:
+                    System.out.println("the file has zero length");
+                    break;
+                case 7:
+                    boolean empty = "".equals(line);
+                    System.out.println("line 7: " + (empty ? "empty" : line));
+                    break;
+                default:
+                    System.out.println("the file has only " + lnum + " line(s)");
+            }
+        }
+    }
+}