Create Check if a Number is Fibonacci Number

Check if a Number is Fibonacci Number

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+// C++ program to check if x is a perfect square
+#include <bits/stdc++.h>
+using namespace std;
+
+// A utility function that returns true if x is perfect
+// square
+bool isPerfectSquare(int x)
+{
+	int s = sqrt(x);
+	return (s * s == x);
+}
+
+// Returns true if n is a Fibonacci Number, else false
+bool isFibonacci(int n)
+{
+	// n is Fibonacci if one of 5*n*n + 4 or 5*n*n - 4 or
+	// both is a perfect square
+	return isPerfectSquare(5 * n * n + 4)
+		|| isPerfectSquare(5 * n * n - 4);
+}
+
+// A utility function to test above functions
+int main()
+{
+	for (int i = 1; i <= 10; i++)
+		isFibonacci(i)
+			? cout << i << " is a Fibonacci Number \n"
+			: cout << i << " is a not Fibonacci Number \n";
+	return 0;
+}
+
+// This code is contributed by Sania Kumari Gupta (kriSania804)