Calculates a double value which is equal to x up to nSignificantDigits significant digits
double prec( double x, int nSignificantDigits )
x with the precision of nSignificantDigits significant digits.
EX1
void prec_ex1() { double x = 34.56789; int nSignificantDigits = 5; printf("prec(%f, %d) = %f", x, nSignificantDigits, prec(x, nSignificantDigits)); }
round
origin.h