hello, I wrote a code that prints a fibonacci sequence

the problem is, when x=71 it prints incorrect result (f[n] != f[n-1] + f[n-2]), it also prints incorrect result for x=76 and after x=79.Code:`#include <math.h>`

#include <stdio.h>

/* http://goldennumber.net/five(5).htm */

#define PHI pow(M_E, asinh(0.5))

/* http://goldennumber.net/five(5).htm */

double fib (unsigned int n)

{

return((pow(PHI, (double)n)) / sqrt(5.0));

}

int main (void)

{

int x; /* counter */

for (x = 0; x < 100; ++x) {

printf("%5d%40.0f\n", x, fib(x));

}

return(0);

}

can anyone help me with this problem?