Create binary_search.cpp

abranhe · web-flow · commit e50588354865 · 2018-09-26T18:38:37.000-04:00
diff --git a/searches/binary_search.cpp b/searches/binary_search.cpp
@@ -0,0 +1,47 @@
+// Binary Search implemented in C++
+// Carlos Abraham Hernandez
+// algorithms.abranhe.com/searches/binary-search
+// repl.it/@abranhe/Binary-Search
+
+#include <iostream>
+using namespace std;
+
+int binary_search(int a[],int l,int r,int key)
+{
+	while(l<=r)
+  {
+		int m = l + (r-l) / 2;
+
+		if(key == a[m])
+			return m;
+		else if(key < a[m])
+			r = m-1;
+		else
+			l = m+1;
+	}
+	return -1;
+}
+
+int main(int argc, char const *argv[])
+{
+	int n, key;
+	cout << "Enter size of array: ";
+	cin >> n;
+	cout << "Enter array elements: ";
+	int a[n];
+	
+  for (int i = 0; i < n; ++i)
+	{
+		cin>>a[i];	
+	}
+	cout << "Enter search key: ";
+	cin>>key;	
+	
+  int res = binary_search(a, 0, n-1, key);
+	
+  if(res != -1)
+		cout<< key << " found at index " << res << endl;
+	else
+		cout << key << " not found" << endl;
+	return 0;
+}
