Take the string input from the user, it should return the first recurring character in it, or "null" if there is no recurring characterFor example, given the string "acbbac" , return "b". Given the string "abcdef", return "null".

Sure, here is a step by step guide on how to solve this problem in Python:

1. First, you need to take a string input from the user. You can use the input() function in Python to do this.

user_input = input("Enter a string: ")

2. Next, you need to iterate over the string and keep track of the characters that you have seen so far. You can use a set in Python to do this. A set is a collection of unique elements.

seen_characters = set()

3. Now, you can iterate over the string using a for loop. For each character, you check if it is in the set of seen characters. If it is, then it is the first recurring character and you return it. If it is not, then you add it to the set of seen characters.

for char in user_input:
    if char in seen_characters:
        print(char)
        break
    seen_characters.add(char)

4. If you iterate over the entire string and do not find a recurring character, then you should return "null". You can do this by using an else clause with the for loop. The else clause will be executed if the for loop completes normally (i.e., it does not encounter a break statement).

else:
    print("null")

Here is the complete code:

user_input = input("Enter a string: ")
seen_characters = set()

for char in user_input:
    if char in seen_characters:
        print(char)
        break
    seen_characters.add(char)
else:
    print("null")

This code will take a string input from the user and print the first recurring character in it, or "null" if there is no recurring character.