函数不是我写的，我想在引用函数后，使用里面i这个值，是在哪里加global i；吗？？？怎么不行哎？求指教！！~
% Take a test vector
function x=jdcdec(y,z)
%clear;clc
%y=[0 1 1 0 1];
% table specified
%table=[2 0 0 0 0 0 0 0 0 0
% 3 0 1 0 0 0 0 0 0 0
% 3 0 1 1 0 0 0 0 0 0
% 3 1 0 0 0 0 0 0 0 0
% 3 1 0 1 0 0 0 0 0 0
% 3 1 1 0 0 0 0 0 0 0
% 4 1 1 1 0 0 0 0 0 0
% 5 1 1 1 1 0 0 0 0 0
% 6 1 1 1 1 1 0 0 0 0
% 7 1 1 1 1 1 1 0 0 0
% 8 1 1 1 1 1 1 1 0 0
% 9 1 1 1 1 1 1 1 1 0];
table=z
N=length(y);
[p,dm1]=size(table);
x=[];
x1=[];
i=1; d=2;tmp=ones(p,1);
while length(x)<64,
% match y(i) to that of the d-th bit in the table
tmp=tmp.*[table(:,d)==y(i)]; % tmp is a vector of 0 and 1 with 1 indicate a match
if sum(tmp)==1, % narrow down to one symbol, find it
d=2; % reset pointer to columns of table.
kkt=0;
for kk=1:length(tmp)
if(tmp(kk)==1),kkt=kk;end
end
cat=kkt-1;
tmp=ones(p,1);
if cat==11,i=i+1;end % Because the comparison ends in last but one column,but still a 0 is left
x1=y(i+1:i+cat);
% Check Range
if(cat ~=0)
x2=bin2int(x1);
if(x2>=2^(cat-1) & x2<2^cat)
x2=x2;
else
x1=ones(1,cat)-x1;
x2=-1*bin2int(x1);
end
else
x2=0;
end
% Update decoded vector
x=[x x2];
i=i+cat;
else
d=d+1;
end
i=i+1;
end
x=filter(1,[1 -1],x); % Inverse of DPCM