x1=rand;
y1=rand;
x2=rand;
y2=rand;
nstep=300;
for i=0:nstep
dx1=(rand*2-1)/10;
dy1=(rand*2-1)/10;
x1=x1+dx1;
y1=y1+dy1;
i=i+1;
dx2=(rand*2-1)/10;
dy2=(rand*2-1)/10;
x2=x2+dx2;
y2=y2+dy2;
i=i+1;
if x1<0 || x1>1
x1=rand;
end
if y1<0 || y1>1
y1=rand;
end
if x2<0 || x2>1
x2=rand;
end
if y2<0 || y2>1
y2=rand;
end
plot(x1,y1,'ob',x2,y2,'ob');axis([0 1 0 1]);
pause(0.1)
if sqrt((x1-x2)^2+(y1-y2)^2)<=0.1
disp('the particles have reacted')
break
end
end