--We can represent a polynomial anxn + an-1xn-1 + : : : + a1x1 + a0
--in Lua as a list of its coefficients, such as {a0,a1,...,an}.
--Write a function that receives a polynomial (represented as a table) and a
--value for x and returns the polynomial value.

function computePoly(poly,x)
local n = #poly --多项式系数个数
local sum = poly[n] --初始化为多项式最高项数对应系数
for i=n-1,1,-1 do
sum = sum * x + poly[i] --循环n-1次
end

return sum
end

print(computePoly({1,2,4,8,16},2))--第1个参数为多项式对应系数，第二个参数为对应x的值