convert decimal number to hexadecimal in c programming

1. #include <stdio.h>
2. #include <stdlib.h>
3. #include <stdbool.h>
4. #include "stack.h"
5.  
6. int main(void)
7. {
8. int num;
9. char alpha;
10. int* digit;
11. STACK* stack;
12.  
13. stack = createStack ();
14.  
15. printf("Please enter your integer (decimal): \n");
16. scanf("%d" , &num);
17.  
18. while(num > 0)
19. {
20. digit = (int*) malloc (sizeof(int));
21. *digit = num % 16;
22. push (stack, digit);
23. num = num/16;
24. }
25.  
26. while (!emptyStack (stack))
27. {
28. digit = (int*)popStack (stack);
29.  
30. if(*digit > 9)
31. {
32. if(*digit == 10)
33. alpha = 'A';
34. else if(*digit == 11)
35. alpha = 'B';
36. else if(*digit == 12)
37. alpha = 'C';
38. else if (*digit == 13)
39. alpha = 'D';
40. else if (*digit == 14)
41. alpha = 'E';
42. else if (*digit == 15)
43. alpha = 'F';
44. }
45.  
46. printf("%c", alpha);
47.  
48. else
49. printf("%d", digit);
50. }
51.  
52. destroyStack(stack);
53. return 0;
54. }