#   h2.py (commnent: #)
def main():
   
    ''' (comment by triple quote string)
    input: built-in function: prompt the user for input
    [1] output a prompt ("hello, darkness my old friend.)
    [2] get the input value from the user.

    =: assignment statement: value in the right hand side is assigned to the variable input_string

    Note: _ can be used in a variable.

    '''   
   
    input_string = input("Please enter a string -> ")
    '''
    Multi-line string.
    It expands many lines.

    print: standard built-in function to print arguments to the standard output.

    f-string in Python. It will evaluate any expression enclosed by { and }.


    s-sting: {len(input_string)} evaluted to 30 and included in the returned string.
    '''
    
    print(f"length of the string: {len(input_string)}")
    '''
    
    '''
    print(f"in upper case: {input_string.upper()}")
    print(f"in lower case: {input_string.lower()}")

#   main() function ends here.
   
if __name__ == "__main__":
    main()