C90 compilant commenting style

challenge/challenge.c

@@ -11,13 +11,13 @@ int main(void) {
 
     printf("Please enter Password: ");
 
-    // read in password from standard input, exit on error.
+    /* read in password from standard input, exit on error. */
     if (getline(&input_line, &input_size, stdin) == -1) {
         perror("Error");
         exit(EXIT_FAILURE);
     }
 
-    // compare password, print info, exit appropriately
+    /* compare password, print info, exit appropriately */
     if (strcmp(input_line, password) == 0) {
         puts("Success!");
         exit(EXIT_SUCCESS);