decimal rounding error in swift 5 code example

Example: xcode truncate number of decimal places of double

//Multiply the double you want to round by 10^(the number of decimal place precision you want), use the "round()" function, then divide by that number again

let x = 1.23556789
let y = Double(round(1000*x)/1000)
print(y)  // 1.236