Python

1: Print Function
2: Escape Sequence
3: Comments
4: Escape Sequence as Normal Text
5: Print Emoji
6: Python as Calculator
7: Strings Concatenation
8: Input
9: int function
10: Variables
11: String Formatting
12: String Indexing
13: String Slicing
14: Step Argument
15: Some useful function and methods
16: Strip Method
17: Find and Replace method
18: Center method
19: If Statement
20: If else statement
21: Nested if-else Statement
22: if-elif-else statement
23: while loop
23.1: Example 1 while loop
23.2: Example 2 while loop
23.3: Example 3 while loop
24: Infinite loop
25: for loop
25.1: Example 1 for loop
26: break and continue statement
27: for loop with string

Chapter 23.2: Example 2 while loop

# printing the sum of digits of a number entered by user.
number = input("Enter a number: ")
length = len(number)
i      = 0
total  = 0
while i < length:
  total = total + int(number[i])
  i    += 1
print(f"The sum of the digits of {number} is {total}")
Output:
Enter a number: 456
The sum of the digits of 456 is 15