Potential error handles.

[326037785]

For the functions in BeizerInterpolation:

1、
unsigned long long int faculty(unsigned int number) {
unsigned long long int f = 1;
for(unsigned int i =1; i <= number; ++i)
f *= i;
return f;
}
The user may input the number which is too large, it needs a alarm for the input"number"
2、
T binomial_coeff(unsigned int n, unsigned int k) {
return faculty(n) / ( faculty(k) * faculty(n-k) );
}
k should be less than n, and when k == n or k == 1, it can return 1 as to reduce complexity.