Resolves for file is piped from std

ccwc.py

@@ -1,57 +1,57 @@
 import argparse
+import sys
 
-def count_lines(filename):
-  with open(filename, 'r') as file:
-    line_count = sum(1 for _ in file)
-  return line_count
-
-def count_words(filename):
-  word_count = 0
-  with open(filename, 'r') as file:
-    for line in file:
-      words = line.split()
-      word_count += len(words)
-  return word_count
-
-def count_chars(filename):
-  with open(filename, 'rb') as file:
-    data = file.read()
-    try:
-      decoded_data = data.decode('utf-8')
-      char_count = len(decoded_data)
-    except UnicodeDecodeError:
-      char_count = len(data)
-    return char_count
-
-def main():
-  parser = argparse.ArgumentParser(prog="ccwc.py", description="Unix word counter", usage="[program] [file] [options]")
-  parser.add_argument('filename', help="Input file")
-  parser.add_argument("-l", "--lines", action='store_true', help="Count the number of lines in the specified file")
-  parser.add_argument("-w", "--words", action='store_true', help="Count the number of words in the specified file")
-  parser.add_argument("-m", "--characters", action='store_true', help="Count the number of characters in the specified file")
-
-  args = parser.parse_args()
-  file = args.filename
-
-  if not(args.lines or args.words or args.characters):
-    line_count = count_lines(file)
-    word_count = count_words(file)
-    char_count = count_chars(file)
-    print(f"{line_count} {word_count} {char_count} {file}")
+def count_lines(lines):
+    line_count = sum(1 for _ in lines)
+    return line_count
 
-  if args.lines:
-    line_count = count_lines(file)
-    print(f"Number of lines in {file}: {line_count}")
+def count_words(lines):
+    word_count = sum(len(line.split()) for line in lines)
+    return word_count
 
-  if args.words:
-    word_count = count_words(file)
-    print(f"Number of words in {file}: {word_count}")
+def count_chars(lines):
+    char_count = sum(len(line) for line in lines)
+    return char_count
 
-  if args.characters:
-    char_count = count_chars(file)
-    print(f"Number of characters in {file}: {char_count}")
+def main():
+    parser = argparse.ArgumentParser(prog="ccwc.py", description="Unix word counter", usage="[program] [file] [options]")
+    parser.add_argument('filename', nargs='?', help="Input file")
+
+    group = parser.add_mutually_exclusive_group()
+    group.add_argument("-l", "--lines", action='store_true', help="Count the number of lines")
+    group.add_argument("-w", "--words", action='store_true', help="Count the number of words")
+    group.add_argument("-m", "--characters", action='store_true', help="Count the number of characters")
+
+    args = parser.parse_args()
+
+    if args.filename:
+        with open(args.filename, 'r') as file:
+            lines = file.readlines()
+    else:
+        lines = sys.stdin.readlines()
+
+    if not (args.lines or args.words or args.characters):
+        line_count = count_lines(lines)
+        word_count = count_words(lines)
+        char_count = count_chars(lines)
+        print(f"{line_count} {word_count} {char_count}")
+    else:
+        if args.lines:
+            line_count = count_lines(lines)
+            print(f"Number of lines: {line_count}")
+
+        if args.words:
+            word_count = count_words(lines)
+            print(f"Number of words: {word_count}")
+
+        if args.characters:
+            char_count = count_chars(lines)
+            print(f"Number of characters: {char_count}")
 
+if __name__ == "__main__":
+    main()
 
 
-if __name__ == "__main__":
-  main()
+# cat test.txt | python ccwc.py -l
+# python ccwc.py test.txt
+# python ccwc.py test.txt -w