Find All Numbers Containing a Given Digit (0–9999)

Program Overview

This Python program reads a single digit (0–9) from the user.
It then scans all integers from 0 to 9999 and prints those that contain the given digit.
This exercise helps practice string conversion, digit matching, and loop iteration.

Python Code:

def find_numbers_with_digit(digit):
    digit_str = str(digit)
    print(f"Numbers containing digit {digit}:")
    for number in range(0, 10000):
        if digit_str in str(number):
            print(number)

# Run the program
digit = int(input("Enter a digit (0–9): "))
if 0 <= digit <= 9:
    find_numbers_with_digit(digit)
else:
    print("Invalid input. Please enter a digit between 0 and 9.")

Sample Output (input: 7):

Numbers containing digit 7:
7
17
27
...
1291
1917
...

Step-by-Step Explanation:

- The program reads a digit from the user
- It converts the digit to a string for easy comparison
- It loops through all numbers from 0 to 9999
- If the digit appears in the number, it prints that number
- The result is a list of all valid integers that contain the specified digit