The decround() function

The decround() function rounds a decimal type number to fractional digits.

Syntax

void decround(d, s)
   dec_t *d; 
   mint s; 
d
A pointer to the decimal structure that contains the value to round.
s
The number of fractional digits to round d. Use a positive integer or zero (0) for this argument.

Usage

The rounding factor is 5x10-s-1. To round a value, the decround() function adds the rounding factor to a positive number or subtracts this factor from a negative number. It then truncates to s digits, as the following table shows.
Value before round Value of s Rounded value
1.4 0 1.0
1.5 0 2.0
1.684 2 1.68
1.685 2 1.69
1.685 1 1.7
1.685 0 2.0