Finding Squareroot of a number without using any maths function(Efficient algorithm)

Squareroot.swift

func squareroot(number: Double) -> Double {
    if number <= 0 {
        return 0
    }
    
    var x = number / 3
    var y = number / x
    let maxDiff: Double = 0.0001
    
    while abs(y - x) > maxDiff {
        x = (x + y) / 2
        y = number / x
    }
    
    return x
}

let squreroot = squareroot(number: 9000000)
print("squreroot = ", squreroot)


//Output:
//squreroot =  3000.00000000004

// while loop is executed only 14 times for a value of 9000000.