C Programming - converting a number to hexidecimal and other bases larger then 10

I'm in the middle of writing a program which converts normal base 10 numbers into any base. When you convert to a base larger then 10 it gets a little confusing how to represent those numbers larger than 10. In hexidecimal the numbers 10 through to 15 are represented as A through to F. Here's a function I have written which converts a number in this way, representing larger then 10 numbers into letters up to Z.

//prints a number in a base using symbols for numbers greater than 10

//similar to hexidecimal. Max base is 36

void printInBaseWithUniqueSymbols (int number, int base){

assert(base > 1);

//find out how many units is needed to make the number

//int numberOfUnits = 1;

int units = base;

while (units <= number) {

//numberOfUnits ++;

units = units * base;

}

    //make an array which contains symbols to use from 1 to base

//using a to z for numbers 10 to 36

    char numberArray [base];

for (int i=0; i

if (i<10) {

numberArray[i]=(48+i);

} else {

numberArray[i]= (65 + (i-10));

}

}

//printf("%c", numberArray[1]);

//work out which how many of each unit

    //int i = 0;

    

int result = number;

while (units > 1) {

units = units / base;

int numberOfUnits = result / units;

//printf("%c", numberOfUnits);

char character = numberArray[numberOfUnits];

printf("%c", character);

result = result % units;

        //i++;

}

}

Results:

Type a starting number: Running…
1
Type an end number: 100
Type a base to count in: 16
1 = 1

2 = 2

3 = 3

4 = 4

5 = 5

6 = 6

7 = 7

8 = 8

9 = 9

10 = A

11 = B

12 = C

13 = D

14 = E

15 = F

16 = 10

17 = 11

18 = 12

19 = 13

20 = 14

21 = 15

22 = 16

23 = 17

24 = 18

25 = 19

26 = 1A

27 = 1B

28 = 1C

29 = 1D

30 = 1E

31 = 1F

32 = 20

33 = 21

34 = 22

35 = 23

36 = 24

37 = 25

38 = 26

39 = 27

40 = 28

41 = 29

42 = 2A

43 = 2B

44 = 2C

45 = 2D

46 = 2E

47 = 2F

48 = 30

49 = 31

50 = 32

51 = 33

52 = 34

53 = 35

54 = 36

55 = 37

56 = 38

57 = 39

58 = 3A

59 = 3B

60 = 3C

61 = 3D

62 = 3E

63 = 3F

64 = 40

65 = 41

66 = 42

67 = 43

68 = 44

69 = 45

70 = 46

71 = 47

72 = 48

73 = 49

74 = 4A

75 = 4B

76 = 4C

77 = 4D

78 = 4E

79 = 4F

80 = 50

81 = 51

82 = 52

83 = 53

84 = 54

85 = 55

86 = 56

87 = 57

88 = 58

89 = 59

90 = 5A

91 = 5B

92 = 5C

93 = 5D

94 = 5E

95 = 5F

96 = 60

97 = 61

98 = 62

99 = 63

100 = 64