diff --git a/c-programming/reverse-ramdisk.c b/c-programming/reverse-ramdisk.c
index c8b0669..ff1618b 100644
--- a/c-programming/reverse-ramdisk.c
+++ b/c-programming/reverse-ramdisk.c
@@ -64,7 +64,7 @@ int tf_alloc(size_t n, size_t type_size) {
 	if (num_temp_files == 0)
 		len_digit = 1;
 	else
-		len_digit = (size_t) ceil(log((double) num_temp_files + 1.) / log(10.));
+		len_digit = (size_t) floor(log10((double) num_temp_files)) + 1;
 	size_t file_path_len = len_digit + strlen("tf_.tmp");
 	char* file_path = malloc((file_path_len + 1) * sizeof(char));
 	if (file_path == NULL) {