Question

Write a program that determines if a string (passed as a command-line argument) has all unique characters. The program must print the number of times each existing character appears, and then print whether or not they are all unique.

Special requirements:
You are NOT allowed to modify the input string or create any additional data structures (no arrays, lists, dictionaries, or other strings).
You may have only one string (the one received as the command-line argument).
You may have one boolean variable and up to 3 integer variables (hint: one is the counter).

DO NOT use any built-in String methods, such as the ones listed here:
https://www.w3schools.com/python/python_ref_string.asp

Input validation: You must print a friendly error message and end execution if the program does not receive any arguments from the command-line.

Here are some sample runs:

C:\>python unique.py
Usage: python unique.py "Any string you want..."
C:\>python unique.py This is a string!
Usage: python unique.py "Any string you want..."
C:\>python unique.py "This is a string!"

T : 1
h : 1
i : 3
s : 3
: 3
i : 3
s : 3
: 3
a : 1
: 3
s : 3
t : 1
r : 1
i : 3
n : 1
g : 1
! : 1

Not unique! One or more characters appear more than once.

Answer 1

import sys # for command line argumets

# length on command line argument 1 then no arguments are provided
if len(sys.argv) == 1:
    # print error
    print("Error: Plase Enter Something After File Name in Command Line!")
else:
    # lets assume all charachtesr are unique in the string
    is_unique = True
    # a loop for iterating over each character
    for i in range(len(sys.argv[1])):
        # count of each char is 0
        counter = 0
        # iterate over the string for each character
        for j in range(len(sys.argv[1])):
            # check if there are any matches
            if sys.argv[1][i] == sys.argv[1][j]:
                # if match then increase the counter
                counter += 1
            # check if count for any character is more than one
            if counter > 1:
                #set is_unique to false
                is_unique = False
        #for each character output the character and its count
        print("{} : {}".format(sys.argv[1][i],counter))
    # check the value of is_unique
    if is_unique:
        # print unique
        print("Unique! all characters only appear once.")
    else:
        # print not unique
        print("Not unique! One or more characters appear more than once.")

# used one boolean and 3 integers variables

# if you have any query regardin this please comment and if you like the answer please upvote :)