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?