I'm converting a double to a char string:

char txt[10];
double num;

num = 45.344322345

sprintf(txt, "%.1f", num);

and using ".1f" to truncate the decimal places, to the tenths digit.
i.e. - txt contains 45.3

I usually use precision in sprintf to ensure the char buffer is not overflowed. How can I do that here also truncating the decimal, without using snprintf?

(i.e. if num = 345694876345.3 for some reason)

Thanks