Problem solving

#1

how to print if a given no. is a fabonnici series or not

#2

@sujeetmandloi23 hey nitin so you wanna to check the number is present in fibonaaci series or not

#3

yes, how to do it ???

#4

@sujeetmandloi23 hey nitin see this
Finding if a number is Fibonacci number or not:

One way to check if a number is Fibonacci is to keep finding Fibonacci numbers till we get a number greater than or equal to. For example, to check if a number ‘n’ is Fibonacci or not:

    int checkfibonacci(int n)
    {
        int a = 0;
        int b = 1;
        if (n==a || n==b) return true;
        int c = a+b;
        while(c<n)
        {
            if(c == n) return true;
            a = b;
            b = c;
            c = a + b;
        }
        return false;
    }

Another method (Quick one) to check if a number if Fibonacci number or not, is as below:

N is a Fibonacci number if and only if ( 5N2 + 4 ) or ( 5N2 – 4 ) is a perfect square!

For Example:

3 is a Fibonacci number since (533 + 4) is 49 which is 77
5 is a Fibonacci number since (555 – 4) is 121 which is 1111
4 is not a Fibonacci number since neither (544 + 4) = 84 nor (544 – 4) = 76 are perfect squares.

#5

where to take input (n)
and give o/p

#6

@sujeetmandloi23 make a main function and in that main function call that function checkfibonacci