Please friends Write a program that input a number and find the number is Fibonacci or not.

Question

Thanks in advance.
hint!
Fibonacci numbers are 1,1,2,3,5,8,....

Answer 1

#include <iostream>
#include <math.h>
using namespace std;

bool isPerfectSquare(int x)
{
int s = sqrt(x);
return (s*s == x);
}

bool isFibonacci(int n)
{
// n is Fibinacci if one of 5*n*n + 4 or 5*n*n - 4 or both
return isPerfectSquare(5*n*n + 4) ||
isPerfectSquare(5*n*n - 4);
}

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;
}