pascal_triangle.rb

def factorial(n)
	return 1 if n==0 || n==1
	i = 1
	(2..n).each {|j| i*=j}
	i
end

def pascalsTriangle(n)
pascal_triangle = []
i=0
while i<n
 	j = 0
 	while j<=i
 		pascal_triangle<<factorial(i)/(factorial(i-j)*factorial(j))
	 	print "#{factorial(i)/(factorial(i-j)*factorial(j))} "
	 	j+=1
	end	
	puts " "
	i+=1
end
pascal_triangle
end
print pascalsTriangle(4)
#   Test.assert_equals(pascalsTriangle(4), [1, 1, 1, 1, 2, 1, 1, 3, 3, 1], "nCr")
# 1  
# 1 1  
# 1 2 1  
# 1 3 3 1 


# all possible pairs
#(1..10).to_a.combination(2).each {|i| print "#{i} "}
# ruby is super cool.