# Find the position of rightmost set bit of number in swift

Swift program for Find the position of rightmost set bit of number. Here problem description and explanation.

``````import Foundation
/*
Swift 4 Program for
Find position of rightmost set bit
*/
class BitPosition
{
// Finding the right most active bit position
func rightmostActiveBit(_ n: Int)
{
if (n <= 0)
{
return;
}
/*
Example
———————
n    = 320
n    = (00101000000)   Binary
-n   = (11011000000)   (2s)
Calculate log2
——————————————
Formula : log(n & -n) / log(2) + 1
-----------------------------------
log(320 & -320) / log(2) + 1)

Here : log(320 & -320) = log(64) = 4.158883
log(2)  = 0.693147

(4.158883 / 0.693147) + 1 = (7) position
————————————————————————————————————————
*/
// Calculate rightmost active bits
let result: Int = Int(log(Double(n & -n)) / log(2.0))+1
print(" Number :",n,"Result :",result);
}
static func main()
{
// Test Cases
// 320 = Binary(101000000)
// (1000) = Binary(1111101000)
// (153) = Binary(10011001)
// (354) = Binary(101100010)
// 160 = Binary(10100000)
}
}
BitPosition.main();``````

Output

`````` Number : 320 Result : 7
Number : 1000 Result : 4
Number : 153 Result : 1
Number : 354 Result : 2
Number : 160 Result : 6``````

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