Added binary search implementation

Algorithms/SearchAlgorithms.h

@@ -4,6 +4,8 @@
 
 #include <iostream>
 #include <vector>
+#include <algorithm>
+#include <iterator>
 
 namespace searchAlgorithms {
 
@@ -73,7 +75,86 @@ namespace searchAlgorithms {
 		return -1;
 	}
 
+	//Search a value in an array
+	//Return its index
+	template<typename T>
+	int binarySearchIndex(std::vector<T> & element, const T& searchValue)
+	{
+		if (element.size() == 0) {
+			throw std::exception("Element size cannot be 0. Cannot perform search");
+			return -1;
+		}
+
+		//Sort the elements before search
+		std::sort(element.begin(), element.end());
+
+		return binarySearchIndexHelper(element, searchValue, 0, element.size());
+	}
+
+	template<typename T>
+	int binarySearchIndexHelper(std::vector<T> & element, const T& searchValue, const size_t startIndex, const size_t endIndex)
+	{
+		if (startIndex > endIndex || startIndex == endIndex)
+			return -1;
 
+		size_t middle = (startIndex + endIndex) / 2;
+
+		if (searchValue == element[middle])
+			return middle;
+		else if (searchValue < element[middle])
+			return binarySearchIndexHelper(element, searchValue, startIndex, middle - 1);
+		else if (searchValue > element[middle])
+			return binarySearchIndexHelper(element, searchValue, middle + 1, endIndex);
+
+		return -1;
+	}
+
+	//Search a value in an array
+	//Return its index
+	template<typename T>
+	bool binarySearchValue(std::vector<T> & element, const T& searchValue)
+	{
+		if (element.size() == 0) {
+			throw std::exception("Element size cannot be 0. Cannot perform search");
+			return false;
+		}
+
+		//Sort the elements before search
+		std::cout << "Sort array before perform searching:\n";
+
+		std::sort(element.begin(), element.end());
+
+		std::cout << "Array after sort:\n";
+		printArray(element);
+
+		//Peform binary search
+		return binarySearchValueHelper(element, searchValue, 0, element.size());
+	}
+
+	template<typename T>
+	bool binarySearchValueHelper(std::vector<T> & element, const T& searchValue, const size_t startIndex, const size_t endIndex)
+	{
+		if (startIndex > endIndex || startIndex == endIndex)
+			return false;
+
+		size_t middle = (startIndex + endIndex) / 2;
+
+		if (searchValue == element[middle])
+			return true;
+		else if (searchValue < element[middle])
+			return binarySearchValueHelper(element, searchValue, startIndex, middle - 1);
+		else if (searchValue > element[middle])
+			return binarySearchValueHelper(element, searchValue, middle + 1, endIndex);
+
+		return false;
+	}
+
+	template<typename T>
+	void printArray(const std::vector<T> & elements)
+	{
+		std::for_each(elements.cbegin(), elements.cend(), [](const T& value) { std::cout << value << " "; });
+		std::cout << "\n\n";
+	}
 }
 
 #endif

Algorithms/main.cpp

@@ -6,21 +6,27 @@
 
 enum testCase
 {
-	LINEAR_SEARCH
+	LINEAR_SEARCH,
+	BINARY_SEARCH
 };
 
 void linearSearchTest();
+void binarySearchTest();
 
 int main()
 {
-	testCase test = LINEAR_SEARCH;
+	testCase test = BINARY_SEARCH;
 
 	switch (test)
 	{
 	case LINEAR_SEARCH:
 		linearSearchTest();
 		break;
 
+	case BINARY_SEARCH:
+		binarySearchTest();
+		break;
+
 	default:
 		break;
 	}
@@ -81,9 +87,63 @@ void linearSearchTest()
 	position = searchAlgorithms::linearSearchIndex(intList, randomValue);
 
 	if (position != -1)
-		std::cout << randomValue << " is on position " << position << " in list\n";
+		std::cout << randomValue << " is on position " << position + 1 << " in list\n";
 	else
 		std::cout << randomValue << " is not exist in list\n";
+}
+
+void binarySearchTest()
+{
+	std::cout << "Linear search test\n\n";
+
+	//Initialize a empty vector to store value
+	std::vector<int> intList;
+
+	//initialize random seeds
+	srand((unsigned int)time(NULL));
+
+	//Push value to the list
+	std::cout << "list contains the followings elements: \n";
+	int randomValue;
+	for (int iter = 0; iter < 20; ++iter) {
+		randomValue = rand() % 250 + 1;
+		intList.push_back(randomValue);
+		std::cout << randomValue << " ";
+	}
+	std::cout << "\n\n";
+
+	//Get one of the value from the list
+	bool exist = searchAlgorithms::binarySearchValue(intList, intList[10]);
+	if (exist)
+		std::cout << intList[10] << " is existed on the list\n";
+	else
+		std::cout << intList[10] << " is not existed on the list\n";
+	std::cout << "\n";
 
+	//Check for invalidate value
+	randomValue = rand() % 500 + 1;
+	exist = searchAlgorithms::binarySearchValue(intList, randomValue);
 
+	if (exist)
+		std::cout << randomValue << " is existed on the list\n";
+	else
+		std::cout << randomValue << " is not existed on the list\n";
+
+	std::cout << "\n";
+	//Get one of the value from the list
+	int position = searchAlgorithms::binarySearchIndex(intList, intList[8]);
+	if (position != -1)
+		std::cout << intList[8] << " is on position " << position << " in list\n";
+	else
+		std::cout << intList[8] << " is not exist in list\n";
+	std::cout << "\n";
+
+	//Check for invalidate value
+	randomValue = rand() % 500 + 1;
+	position = searchAlgorithms::binarySearchIndex(intList, randomValue);
+
+	if (position != -1)
+		std::cout << randomValue << " is on position " << position + 1 << " in list\n";
+	else
+		std::cout << randomValue << " is not exist in list\n";
 }