gusucode.com > 《精通matlab 7》包括配套光盘 > 配套光盘里的程序附件/Ex-30/testclass/@polynom/minus.m

    function r = minus(p,q)
% POLYNOM/MINUS 执行多项式的 p-q.
p = polynom(p);
q = polynom(q);
k = length(q.c) - length(p.c);
r = polynom([zeros(1,k) p.c] - [zeros(1,-k) q.c]);