Lines of Code

Lines of Code

This Python program is an implementation to CS50’s Introduction to Programming with Python Week 6 - Lines of Code Problem Set. The lines.py program takes the name of a Python file as a command-line argument and outputs the number of lines of code in that file, excluding comments and blank lines.

How to Run the Program

1. Open your terminal.

2. Navigate to the directory where you have saved the lines.py file.

   cd path/to/your/directory
   

3. Run the program using the python command and provide the filename as an argument:

   python lines.py filename.py
   

   Replace filename.py with the actual name of the Python file you want to analyze.

Program Code

lines.py

import sys

def main():
    # Check for the correct number of command-line arguments
    if len(sys.argv) != 2:
        sys.exit("Usage: python lines.py filename.py")

    filename = sys.argv[1]

    # Check if the filename ends with .py
    if not filename.endswith(".py"):
        sys.exit("Not a Python file")

    try:
        with open(filename, "r") as file:
            code_lines = count_code_lines(file)
            print(f"Number of lines of code in {filename}: {code_lines}")
    except FileNotFoundError:
        sys.exit("File does not exist")

def count_code_lines(file):
    code_lines = 0
    in_comment = False

    for line in file:
        stripped_line = line.strip()

        # Skip blank lines
        if not stripped_line:
            continue

        # Skip comment lines
        if stripped_line.startswith("#"):
            continue

        # Handle multi-line comments
        if stripped_line.startswith("'''") or stripped_line.startswith('"""'):
            in_comment = not in_comment

        if not in_comment:
            code_lines += 1

    return code_lines

if __name__ == "__main__":
    main()

How to Test

1. Follow the steps mentioned in the "How to Run the Program" section to run the lines.py program.
2. Provide the name of a Python file that you want to analyze (e.g., hello.py) as a command-line argument.
3. The program will output the number of lines of code in the specified file, excluding comments and blank lines.

Additional Notes

• The lines.py program uses the sys module to handle command-line arguments and exit the program if necessary.
• The program also handles different cases of comments, including multi-line comments enclosed in triple quotes (''' or """).
• The count_code_lines function counts the lines of code in the provided file, excluding comments and blank lines.
• After running the program, it will display the count of code lines in the specified Python file.