Instance Method

round(_:)

Rounds the value to an integral value using the specified rounding rule.

Declaration

mutating func round(_ rule: FloatingPointRoundingRule)

Parameters

rule

The rounding rule to use.

Discussion

The following example rounds a value using four different rounding rules:

// Equivalent to the C 'round' function:
var w = 6.5
w.round(.toNearestOrAwayFromZero)
// w == 7.0

// Equivalent to the C 'trunc' function:
var x = 6.5
x.round(.towardZero)
// x == 6.0

// Equivalent to the C 'ceil' function:
var y = 6.5
y.round(.up)
// y == 7.0

// Equivalent to the C 'floor' function:
var z = 6.5
z.round(.down)
// z == 6.0

For more information about the available rounding rules, see the FloatingPointRoundingRule enumeration. To round a value using the default “schoolbook rounding”, you can use the shorter round() method instead.

var w1 = 6.5
w1.round()
// w1 == 7.0

Relationships

From Protocol