C language: enter a positive integer with uncertain digits to flip the digits!

Code:

1. /* Give a positive integer with the following requirements:
2. 1. Find the number of digits;
3. 2. output each digit separately;
4. 3. output the numbers in reverse order,
5. */
7. # Include <stdio. h>
8. # Include <math. h>
10. Void main ()
11. {
12. Int A, B, C, D, I = 0;
13. Int sum = 0;
14. Int * P = new int [];
16. Printf ("enter a number :");
17. Scanf ("% d", & );
19. // Determine the number of digits;
20. Do {
21. I ++;
22. P [I] = A % 10;
23. A = A/10;
24. } While (! = 0 );
26. // Output the value in the dynamic array
27. D = I;
28. While (D! = 0 ){
30. Printf ("% d,", P [d]);
31. D --;
32. }
33. Printf ("the number of digits is % d/N", I );
36. // Print this value using the reverse string. Use the POW function POW (x, y) --> Y of X;
37. For (C = 1; C <= I; C ++ ){
38. B = POW (10, C-1 );
39. Sum = B * P [c] + sum;
40. Printf ("% d/N", sum );
41. }
43. Delete [] P;
45. }

Here I think of the dynamic array method to save the result of each remainder operation. It seems like a pointer also works. I don't have to remember it for a long time!

The method for attaching a dynamic array is as follows:

Int main ()
{
// Use the pointer P to point to the new dynamically allocated memory space with the length Len * sizeof (INT)
Int * P = new int []; // if it is C ++, the system will warn that no array length is specified.
...........
Delete [] P;
Return 0;
}