use 5.010; 
use strict; 
use warnings; 
open(FILE, "<:encoding(UTF-8)", "aa.txt") or die "Could not open file: $!"; 
my $numbers; 
while (<FILE>) { 
    $numbers="$_" ; 
    print "$_"; 
} 
chomp $numbers; 
print "\n$numbers"; 
my $len=length($numbers); 
print "\n$len\n"; 
my $i; 
my $abc; 
foreach my $i (0..$len){ 
    foreach my $j (1..6) { 
        print "$j----->"; 
        $abc = substr($numbers,$i,$j); 
        print "$abc\n"; 
    } 
    print "***********************************\n"; 
} 
close FILE;

##</code><code>##

// C++ program to check if x is a perfect square 

#include <iostream> 
#include <math.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 Fibinacci Number, else false 
bool isFibonacci(int n) { 
    // n is Fibinacci if one of 5*n*n + 4 or 5*n*n - 4 or both 
    // is a perferct 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; 
}