write function for fast exponentiation in cpp

Bit-manipulationTechniques/FastExponentiation/main.cpp

@@ -0,0 +1,31 @@
+#include <iostream>
+
+using namespace std;
+
+int fastExponentiation(int a, int n)
+{
+    int ans = 1;
+
+    while (n > 0)
+    {
+        int lastBit = n & 1;
+
+        if (lastBit)
+            ans *= a;
+
+        a *= a;
+        n = n >> 1;
+    }
+
+    return ans;
+}
+
+int main()
+{
+    int a, n;
+    cin >> a >> n;
+
+    cout << fastExponentiation(a, n) << endl;
+
+    return 0;
+}