In computer science, binary search, also known as half-interval search or logarithmic search, is a search algorithm that finds the position of a target value within a sorted array

binarySearch.go

package binary

import (
	"errors"
	"sort"
)

// BinarySearch search binary
func BinarySearch(data []int, searchValue int) (int, error) {
	firstIndex := 0
	lastIndex := len(data) - 1

	if lastIndex == -1 {
		return 0, errors.New("Data can not be empty")
	}

	sort.Ints(data)
	if searchValue > data[lastIndex] {
		return 0, errors.New("Searching bigger that values in slice")
	}

	var stepIndex int
	for firstIndex <= lastIndex {
		stepIndex = (firstIndex + lastIndex) / 2

		if data[stepIndex] == searchValue {
			return stepIndex, nil
		}

		if searchValue > data[stepIndex] {
			firstIndex = stepIndex + 1
		} else {
			lastIndex = stepIndex - 1
		}
	}

	return 0, errors.New("Searching value not found")
}