如何在matlab中用蒙特卡洛模拟计算欧式期权价格

function [c,p]=ucoption(S,X,sigma,r,T,M)
sig2=sigma^2;
srT=sqrt(T);
srTa=sigma*srT;
c=0;
p=0;
for i=1:M
ST=S*exp((r-0.5*sig2)*T+srTa*randn);
c=c+max(ST-X,0);