please explain this code.

clear;
%%%%%%%%%%%%%%%%%%%%%%%%%%%Modified LEACH%%%%%%%%%%%%%%%%%%%%%%
xm=400;      %diameters of sensor network
ym=400;

sink.x=200;  %distance of base station from the network
sink.y=200;

n = 100;         %no of nodes

p=0.1;          %probibilty of a node to become cluster head

Eo=0.5;          %energy supplied to each node
ch=n/10;
ETX=50*0.000000001;     %transmiter energy per node
ERX=50*0.000000001;        %reciever energy per mode

Efs=10*0.000000000001;     %amplification energy when d is less than d0
Emp=0.0013*0.000000000001;      %amplification energy  when d is greater than d0
Efs1=Efs/10;   % amp energy just for intra cluster communication.
Emp1=Emp/10;
%Data Aggregation Energy
EDA=5*0.000000001;

a=Eo/2;                %?

rmax=2500;           %no of rounds
%temprature range
tempi=50;
tempf=200;

%Thresholod for transmiting data to the cluster head
h=100;                                 %%%%%%Hard Thres%%%%hold H(t)
s=2;                                   %%%%%%Soft thres%%%%hold  S(t)

sv=0;                                  %%%%%%previously Sensed value S(v)

do=sqrt(Efs/Emp);       %distance between cluster head and base station
do1=sqrt(Efs1/Emp1);    
for i=1:1:n
 S(i).xd=rand(1,1)*xm;         %it will distribute the nodes in 1 dimension in x axis randomly.
 XR(i)=S(i).xd;                 %we store its value in xr  
 S(i).yd=rand(1,1)*ym;           %it will distribute the nodes in 1 dimension in y axis randomly 
 YR(i)=S(i).yd;
 S(i).G=0;                        % as the no of node that have been cluster head is zero 0
 S(i).E=Eo%%*(1+rand*a);                %?
 %ch.E=x; % initial energy of all cluster heads in network
 %initially there are no cluster heads only nodes
 S(i).type='N';
end

S(n+1).xd=sink.x;   %assume that base station is also a node sp total no of nodes is n and with base station  it is n+1
S(n+1).yd=sink.y;

countCHs=0;         %the number of Stateflow objects in the current context.
cluster=1;              %first cluster is selected
flag_first_dead=0;         
flag_teenth_dead=0;
flag_all_dead=0;

dead=0;
first_dead=0;
teenth_dead=0;
all_dead=0;

allive=n;
%counter for bit transmitted to Bases Station and to Cluster Heads
packets_TO_BS=0;
packets_TO_CH=0;
for r=0:1:rmax
      cv = tempi + (tempf-tempi).*rand(1,1);  %%%%%%Current sensing value C(v)
 if(mod(r, round(1/p) )==0) %remainder
 for i=1:1:n
     S(i).G=0;            % it will assign to the nodes that have not been cluster head .
     %%S(i).cl=0;
 end
 end

dead=0;
for i=1:1:n

   if (S(i).E<=0)
       dead=dead+1;

       if (dead==1)
          if(flag_first_dead==0)
             first_dead=r;
             flag_first_dead=1;
          end
       end

       if(dead==0.1*n)
          if(flag_teenth_dead==0)
             teenth_dead=r;
             flag_teenth_dead=1;
          end
       end
       if(dead==n)
          if(flag_all_dead==0)
             all_dead=r;
             flag_all_dead=1;
          end
       end
   end
   if S(i).E>0
       S(i).type='N';
   end
end
STATISTICS.DEAD(r+1)=dead;
STATISTICS.ALLIVE(r+1)=allive-dead;

countCHs=0;
cluster=1;

if   S(i).type=='C' && S(i).E>a
for j=1:1:ch
  countCHs=countCHs+1;
  S(i).type='C';
         S(i).G=round(1/p)-1;
         C(cluster).xd=S(i).xd;
         C(cluster).yd=S(i).yd;
  distance=sqrt( (S(i).xd-(S(n+1).xd) )^2 + (S(i).yd-(S(n+1).yd) )^2 );
         C(cluster).distance=distance;
         C(cluster).id=i;
         X(cluster)=S(i).xd;
         Y(cluster)=S(i).yd;
         cluster=cluster+1;
distance;

    %   if (cv >= h)
 %test = cv-sv;
 %if (test >= s)
           if (distance>do)
               S(i).E=S(i).E- ( (ETX+EDA)*(4000) + Emp*4000*(distance*distance*distance*distance ));
           end
           if (distance<=do)
               S(i).E=S(i).E- ( (ETX+EDA)*(4000)  + Efs*4000*(distance * distance ));
           end
           %end

           %packets_TO_BS=packets_TO_BS+1;
           %PACKETS_TO_BS(r+1)=packets_TO_BS;
            %          packets_TO_CH=packets_TO_CH+1;
end
else
for i=1:1:n        
  if(S(i).E>0)
  temp_rand=rand;
  if ( (S(i).G)<=0)

       if(temp_rand<= (p/(1-p*mod(r,round(1/p)))))
           countCHs=countCHs+1;
           packets_TO_BS=packets_TO_BS+1;
           PACKETS_TO_BS(r+1)=packets_TO_BS;
            S(i).type='C';
           S(i).G=round(1/p)-1;
           C(cluster).xd=S(i).xd;
           C(cluster).yd=S(i).yd;
          distance=sqrt( (S(i).xd-(S(n+1).xd) )^2 + (S(i).yd-(S(n+1).yd) )^2 );
           C(cluster).distance=distance;
           C(cluster).id=i;
           X(cluster)=S(i).xd;
           Y(cluster)=S(i).yd;
           cluster=cluster+1;

    %   if (cv >= h)
 %test = cv-sv;
 %if (test >= s)

           distance;
           if (distance>do)
               S(i).E=S(i).E- ( (ETX+EDA)*(4000) + Emp*4000*(distance*distance*distance*distance ));
           end
           if (distance<=do)
               S(i).E=S(i).E- ( (ETX+EDA)*(4000)  + Efs*4000*(distance * distance ));
           end
       end
       end
  % end
   % S(i).G=S(i).G-1;

end
end
end
STATISTICS.COUNTCHS(r+1)=countCHs;

for i=1:1:n
if ( S(i).type=='N' && S(i).E>0 )
  if(cluster-1>=1)
    min_dis=Inf;
    min_dis_cluster=0;
    for c=1:1:cluster-1
        temp=min(min_dis,sqrt( (S(i).xd-C(c).xd)^2 + (S(i).yd-C(c).yd)^2 ) );
        if ( temp<min_dis )
            min_dis=temp;
            min_dis_cluster=c;
        end
    end
% if (cv >= h)
%test = cv-sv;
%if (test >= s)
         min_dis;
         if (min_dis>do1)
             S(i).E=S(i).E- ( ETX*(4000) + Emp1*4000*( min_dis *min_dis * min_dis * min_dis));
         end
        if (min_dis<=do1)
             S(i).E=S(i).E- ( ETX*(4000) + Efs1*4000*( min_dis * min_dis));
         end
                S(C(min_dis_cluster).id).E =S(C(min_dis_cluster).id).E- ( (ERX + EDA)*4000 );
         packets_TO_CH=packets_TO_CH+1;
%end
%sv

       S(i).min_dis=min_dis;
       S(i).min_dis_cluster=min_dis_cluster;
   else
       min_dis=sqrt( (S(i).xd-S(n+1).xd)^2 + (S(i).yd-S(n+1).yd)^2 );
           if (min_dis>do)
               S(i).E=S(i).E- ( ETX*(4000) + Emp*4000*( min_dis *min_dis * min_dis * min_dis));
           end
           if (min_dis<=do)
               S(i).E=S(i).E- ( ETX*(4000) + Efs*4000*( min_dis * min_dis));
           end
           packets_TO_BS=packets_TO_BS+1;

sv=cv;
  end
end
end
STATISTICS.PACKETS_TO_CH(r+1)=packets_TO_CH;
STATISTICS.PACKETS_TO_BS(r+1)=packets_TO_BS;
end
first_dead;
teenth_dead;
all_dead;
STATISTICS.DEAD(r+1)
STATISTICS.ALLIVE(r+1)
STATISTICS.PACKETS_TO_CH(r+1)
STATISTICS.PACKETS_TO_BS(r+1)
STATISTICS.COUNTCHS(r+1)

r=0:rmax;
figure (1);
plot(r,STATISTICS.DEAD);
xlabel('Rounds');
ylabel('Dead Nodes');
title('MODLEACH');
figure (2);
plot(r,STATISTICS.PACKETS_TO_BS);
xlabel('Rounds');
ylabel('Packets to BS');
title('MODLEACH');
figure (3);
plot(r,STATISTICS.COUNTCHS);
xlabel('Rounds');
ylabel('Number of Cluster Heads');
title('MODLEACH');
figure (4);
plot(r,STATISTICS.PACKETS_TO_CH);
xlabel('Rounds');
ylabel('Packets to CH')
title('MODLEACH');
figure (5);
plot(r,STATISTICS.ALLIVE);
xlabel('Rounds');
ylabel('Allive nodes')
title('MODLEACH');
%subplot(2,2,1);
%plot(r,STATISTICS.DEAD);
%xlabel('Rounds');
%ylabel('Dead Nodes ');
%subplot(2,2,2);
%plot(r,STATISTICS.PACKETS_TO_CH);
%xlabel('Rounds');
%ylabel('Packets to CH');
%legend('Mod LEACH ST');   %,'LEACH'
%subplot(2,2,3);
%plot(r,STATISTICS.PACKETS_TO_BS);
%xlabel('Rounds');
%ylabel('Packets to BS');
%subplot(2,2,4);
%plot(r,STATISTICS.COUNTCHS);
%xlabel('Rounds');
%ylabel('Number of Cluster Heads');
%title('\bf LEACH');%

[Azzi Abdelmalek]

What answer are you expecting? clarify what you want.

[Jan]

@tejasvee: I agree with Azzi. Do you expect us to explain each line of code?! It is rather unlikely that somebody spends the time for this, when you do not show any own effort.

[John D'Errico]

Questions like this are inappropriate here. Someone could spend weeks writing up a detailed explanation, when perhaps all you needed was an overview anyway. If you want to understand the code, then it is time for you to learn MATLAB. Start doing your own work. Make an effort.