Go Binary Search

binarySearch.go

package main

import (
	"fmt"
	"math"
)

func main() {
	fmt.Println("index", binarySearch([]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, 8))
}

func binarySearch(intSlice []int, value int) int {
	lowerBound := 0
	upperBound := len(intSlice) - 1

	for lowerBound <= upperBound {
		midIndex := math.Floor(float64((lowerBound + upperBound) / 2))
		valueAtMid := intSlice[int(midIndex)]

		if value == valueAtMid {
			return int(midIndex)
		} else if value < valueAtMid {
			upperBound = int(midIndex) - 1
		} else if value > valueAtMid {
			lowerBound = int(midIndex) + 1
		}
	}
	return -1
}