update math with itoa base

module05/ex02/math.c

@@ -8,25 +8,34 @@ void int_to_hex_string(uint64_t value, char *out, uint8_t num_digits) {				// nu
     out[num_digits] = '\0';
 }
 
-void int_to_string(uint64_t value, char *buffer) {
+void int_to_string_base(uint64_t value, char *buffer, uint8_t base) {				// buffer must have the right size
+    if (base < 2 || base > 36) {
+        buffer[0] = '\0';															// unsupported base
+        return;
+    }
+
     // handle zero case
     if (value == 0) {
         buffer[0] = '0';
+        buffer[1] = '\0';
 		return;
     }
 
-	uint8_t size = -1;
+	uint8_t size = 0;
 	uint64_t copy = value;
 
 	while (copy) {
-		copy /= 10;
+		copy /= base;
 		size++;
 	}
 
+    buffer[size] = '\0';															// null-terminate the string
+    size--;																			// adjust index for last digit
+
 	while (value) {
-		uint8_t digit = value % 10;
-		buffer[size] = digit + '0';
-		value /= 10;
+		uint8_t digit = value % base;
+		buffer[size] = digit < 10 ? ('0' + digit) : ('A' + digit - 10);
+		value /= base;
 		size--;
 	}
-}
+}