matlab中出现Undefined function or variable 'X'.请高人帮忙分析下，谢谢

函数本身存在错误，修改后，将下面函数保存为ispoiy.m。 function C=ispoiy(X,Y,M) %Input -X is the 1xn abscissa vector % -Y is the 1xn ordinate vector % -M is the degree of the least-squares polynomial %Output-C is the coefficient list for the polynomial n=length(X