I have a problem in solving these C++ Program.

The binomial expression can be expanded as follows
If n=2 a2+2ab+b2
1 2 1
1 3 3 1
The coefficients will be gotten using the combination ncm and its refered to as the pascal triangle
Such that if n=4 then;
4c0 4!/(4-0)!0!=1
4c1 4!/(4-1)!1!=4
4c2 4!/(4-2)!2!=6

1. write a function to compute the combinations
2. implement it in c++ program to output the pascal triangle for a number n.