Calculate simple math equation

Question

I try to use swift code to calculate 10 * 75% = 7.5

var b : Int = 10
var a : Int = 75
// result x is 0
var x = b * (a / 100)

However the result is zero. How to get 7.5 result without changing the type and value of a and b?

UPDATE:

I got it right by:

 var x: Double = (Double(b) * (Double(a) / 100)) // x is 7.5

Now, how can I round it to 8 as a Int type?

But I didn't claim x is an integer type. I expected swift is smart to assign the right type to x — Leem, Mar 12 '18 at 15:40
Swift did assign the right type to x, an `Int` divided by an `Int` is an `Int` — dan, Mar 12 '18 at 15:41
Swift is smart enough. You are doing `Int` math so `x` is an `Int`. — rmaddy, Mar 12 '18 at 15:41
BTW - your use of `: Int` for `a` and `b` is redundant. `var b = 10` will automatically make `b` the type `Int`. — rmaddy, Mar 12 '18 at 15:42
Not being serious, but this fulfills the requirements: `var x = b * a / 100; if (b * a % 100) >= 50 { x += 1 }` — vadian, Mar 12 '18 at 16:09
It is simple. In the same way you converted a and b to Double, convert x to an int with ` print(Int(x)) ` — Michael, Mar 12 '18 at 16:15

score 0 · Answer 1 · edited Mar 12 '18 at 15:46

0

You're using integer (i.e. whole number) arithmetic, when what you want is floating-point arithmetic. Change one of the types to Float, and Swift will figure out that x is also a Float.

var b : Int = 10
var a : Int = 75
var x = Float(b) * (Float(a) / 100.0) // now x is a Float (.75)

edited Mar 12 '18 at 15:46

rmaddy

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answered Mar 12 '18 at 15:42

NRitH

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Norman G · Answer 2 · 2018-03-12T15:57:20.963

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Ok then you just need to do:

var b : Int = 10
let c = (Double(b) * 0.75)
let restult = ceil(c)

edited Mar 12 '18 at 15:57

answered Mar 12 '18 at 15:46

Norman G

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score 0 · Answer 3 · answered Mar 12 '18 at 15:49

0

For doing arithmetic in Swift, both sides of the equation must be using the same type. Try using this code:

let b = 10.0
let a = 75.0
let x = b * (a / 100.0
print(x)

7.5

To make it round up, use the built in ceil function

print(ceil(x))

8.0

answered Mar 12 '18 at 15:49

Scriptable

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Calculate simple math equation

3 Answers3