algorithm to print the digits in the correct order

Question

I've been trying to write an algorithm that will print separately the digits from an integer. I have to write it in Pseudocode. I know how to write an algorithm that reverse the digits.

digi(n): 
  while n != 0:
    x = n % 10 
    n = n // 10 
    print (x)

But I don't know how to write an algorithm to print the digits in the correct order. For example, the input is integer 123467 and the output is: 1 2 3 4 6 7. The numbers will be input from the user, and we cannot convert them to a string. I need help getting started on writing algorithms.

Answer 1

log n will give you the number of (decimal) digits in n.

Notice that 1234 / (10^[4-1]) = 1.234 which rounds down to 1. Repeat as necessary (mod 10) to print each digit.

• 1.234 -> 1
• 12.34 % 10 -> 2.34 -> 2
• 123.4 % 10 -> 3.4 -> 3
• 1234 % 10 -> 4

Answer 2

If you already have an algorithm to print them in reverse put them in a stack and then print the stack which will reverse the order.

Answer 3

The usual algorithm is to write a recursive function which recurses with n/10 and then prints n%10. Extra credit for correctly handling negative numbers.

Answer 4

Recursive method

function print_straightforward
if(N<10)
  print N
else
  print_straightforward(N/10);
  print N%10