%x in format string (no. 1) requires 'unsigned int *' but the argument type is 'signed int *'.

This error occurs when you use the `%x` format specifier in a printf or scanf function with a signed integer argument instead of an unsigned integer argument.

To fix this error, you can either change the format specifier to `%d` (for signed integers) or change the argument type to an unsigned int pointer by adding a cast to `(unsigned int *)`. For example:

signed int num = -10;
printf("The number in hexadecimal is: %x\n", (unsigned int)num); // using a cast to convert the signed int to an unsigned int