BinarySearch.swift

var numbers = [Int]()

for x in 1...100 {
    numbers.append(x)
}

var num = [1,2,4,6,8,9,11,13,16,17,20]

func binarySearch(for searchValue: Int, withDatasoucre datasource: [Int]) -> Bool {
    var firstIndex = 0
    var lastIndex = datasource.count - 1
    
    while firstIndex <= lastIndex {
        
        let middleIndex = (firstIndex + lastIndex) / 2
        let middleValue = datasource[middleIndex]
        
        print("middleValue: \(middleValue), firstIndex: \(firstIndex), lastIndex: \(lastIndex), [\(datasource[firstIndex]),\(datasource[lastIndex])]")
        
        if middleValue == searchValue {
            return true
        }
        if searchValue < middleValue {
            lastIndex = middleIndex - 1
        }
        
        if searchValue > middleValue {
            firstIndex = middleIndex + 1
        }
    }
    
    return false
}

func searchValueIsFound(x: Int, y: Int) -> Bool {
    if x == y {
        return true
    }
    return false
}
let searchValue: Int = 4101
print(binarySearch(for: searchValue, withDatasoucre: numbers))