long type negative value occurance

[mcad]

Hi all,
I am displaying the speed and the duty cycle of the dc motor.
But, in spite of making the speed variable long data type, it sometimes displays negative numbers. So, would you please tell me how I can fix it ?

[PCM programmer]

Use "%lu" to display unsigned 16-bit values. Don't use "%ld".

[mcad]

thanks sir.
But, I also saw "%04lu" . which is better to use sir ?

[Ttelmah]

The '04', just says how many digits to always display, and to use leading zeros. 'u' means to treat the value given as an unsigned value, while 'd' says to treat it as a signed value. The 'key' is to understand that the output specification, is independant of the real 'type' of the internal number. Hence if you have a value of (hex) FFFF, and display this using 'ld', it gets printed as -1, while the same internal value, if printed with 'lu', gets displayed as 65535.
I you have a value of '0', and print it with %lu, you get '0' displayed, but use %04lu, and '0000' gets displayed.

Best Wishes

[mcad]

Thanks very much sir for your clarification.

Regards