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Michael Paniccia
Michael Paniccia

Reputation: 931

How to easily make a function round to the nearest hundredth

Hello I am making a calculator app and I need a way to round the answer to the second number

Upvotes: 1

Views: 1243

Answers (2)

MirekE
MirekE

Reputation: 11555

If you need to round just for display, you can use either NSNumberFormatter or String formatting capability:

let number = 123.456789

let formatter = NSNumberFormatter()
formatter.minimumFractionDigits = 0
formatter.maximumFractionDigits = 2

formatter.stringFromNumber(number)  // "123.46"
String(format: "%.2f", number)      // "123.46"

Upvotes: 4

ezig
ezig

Reputation: 1229

Double(round(num*100)/100)

Should work. The way this works is first it multiplies by 100, which shifts all of the digits over to the left two places. Then it rounds based on the first decimal digit which is now the thousandths place. Then dividing by 100 again will shift everything to the right two decimal places.

This is the same as if you had just looked at the thousandths place and rounded to the nearest hundredth based on that (which is how a human would do it)

Upvotes: 1

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