[sjzyanliang]

clear
t=0:1:20;
A=zeros(size(t)); %给A充零
B=zeros(size(t)); %给B充零
B=B+8;


for t=7:12 %使得A(7)至A(12)全部等于8;
A(t)=B(t);
end
t=1:21
A
plot(t,A,'o',t,A)%显示图线