朋友们，帮我讲讲case_of 中的命令流吧，谢谢了
def parm
nptab1=7
nprof=10
end
parm
table 1 12 0 18.25 12.5 25 17 35 21 50 24 75 25 150 25
def aux1
loop n(1,nptab1)
rr=xtable(1,n)
zz=ytable(1,n)
loop k(1,nprof)
case_of k
alfa=0.5*(pi+.1)*float(k-2)/float(nprof-2)
xtable(n+10,k)=rr*cos(alfa)
ytable(n+10,k)=rr*sin(alfa)
case 1
xtable(n+10,k)=rr
ytable(n+10,k)=-40.0
case 2
xtable(n+10,k)=rr
ytable(n+10,k)=0.0
end_case
end_loop
end_loop
end
aux1
