Q.Program 10-8: Write a function to convert a number entered by the user into its corresponding number in words. For example, if the input is 876 then the output should be ‘Eight Seven Six’.

Keep the number as a string so we can loop digit by digit; a dictionary maps each digit 0-9 to its word, and the function assembles the words in order:

def convert(num):
    numberNames = {0: 'Zero', 1: 'One', 2: 'Two', 3: 'Three', 4: 'Four',
                   5: 'Five', 6: 'Six', 7: 'Seven', 8: 'Eight', 9: 'Nine'}
    result = ''
    for ch in num:
        result = result + numberNames[int(ch)] + ' '
    return result.strip()

num = input("Enter any number: ")
print("The number in words is:", convert(num))
``` …

The idea. The mapping digit -> word is fixed and small, which is exactly what a dictionary literal is for. The subtle design choice is to not convert the input to int: keeping num as a string lets us iterate over it character by character, and each character is turned into the integer key with int(ch). This also preserves leading zeros (int('076') would lose the 0).

Program 10-8:

def convert(num):
    numberNames = {0: 'Zero', 1: 'One', 2: 'Two', 3: 'Three', 4: 'Four',
                   5: 'Five', 6: 'Six', 7: 'Seven', 8: 'Eight', 9: 'Nine'}
    result = ''
    for ch in num:                       # num is a string, so we can loop over digits
        result = result + numberNames[int(ch)] + ' '
    return result.strip()

num = input("Enter any number: ")
print("The number is:", num)
print("The number in words is:", convert(num))

Sample run:

Enter any number: 876
The number is: 876
The number in words is: Eight Seven Six

Trace for input '876':

| ch | int(ch) | numberNames lookup | result so far |

|-----|---------|--------------------|----------------------| …