for cishu=1:1000
        p=rand(k,2);
        c=Connect(p,r);
        liantong=liantong+c;
        end
    liantonglv(i)=liantong/1000;        
    plot(r,liantonglv(i),'b-*')
 

function [ C ] = Connect( graph,r ) 
adjmatrix=1.-im2bw(squareform(pdist(graph)),r); %生成邻接矩阵  
len=size(adjmatrix,1);  
quit=0;  
for n=1:len   
    if sum(adjmatrix(n,:))==1      %排除孤立点  
        quit=1;  
    end  
end

%判断连通性
if quit~=1  
    connected(len)=0; %已连接节点  
    connected(1)=1;  
    connected=findconnected(1,adjmatrix,connected);%找到与节点1连接的节点  
    if sum(connected)==len  
        C=1;  
    else  
        C=0;  
    end  
else  
    C=0;  
End

function [connected]=findconnected(start,adjmatrix,connected)
leaf=find(adjmatrix(start,:)==1);%找出与节点start直接相连的节点  
len=size(leaf,2) ; 
flag=0;  
nflag=1;  
for n=1:len  
if connected(leaf(n))==0;%若节点已在连接向量（connected）中则跳过  
    flag(nflag)=leaf(n);  
    nflag=nflag+1;  
end  
end  
len=size(flag,2) ; 
if flag~=0  
for n=1:len  
    connected(flag(n))=1;  
end  
for n=1:len  
connected=findconnected(flag(n),adjmatrix,connected);%查找当前节点的子节点  
end  
end