programming assignment

[DeaD_EyE]

Reading data from four files line by line sounds cool. This remind me to look into contextlib.
Example without modification of data:

import contextlib
import sys


def read_files_iterative(filenames):
    with contextlib.ExitStack() as stack:
        try:
            files = [stack.enter_context(open(fname)) for fname in filenames]
        except (FileNotFoundError, PermissionError) as e:
            print(e, file=sys.stderr)
            raise
        for data in zip(*files):
            yield data

def main():
    if len(sys.argv) != 5:
        print('4 Filenames are required')
        return 1
    filenames = sys.argv[1:5]
    try:
        for row in read_files_iterative(filenames):
            print(row)
    except:
        return 2
    # putting them into a list:
    # content = list(read_files_iterative(filenames))
    # print(content)
    return 0

if __name__ == '__main__':
    # be a nice shell citizen and return an error code
    sys.exit(main())

Conclusion: This code won't help you and it does not fit to your professors requirements.