Hi Linu Pinto,
You could plot each section separately.
x = -10:0.1:10;
y = sin(x);
z(y<0) = 1;
z(y>=0) = 0;
nZNew =[0 find(diff(z) ~= 0) length(z)];
zNew = arrayfun(@(nStart,nEnd) z(nStart+1:nEnd),nZNew(1:end-1),nZNew(2:end),'UniformOutput',false);
xNew = arrayfun(@(nStart,nEnd) x(nStart+1:nEnd),nZNew(1:end-1),nZNew(2:end),'UniformOutput',false);
fh = figure;
ah = axes(fh);
hold(ah,'on');
cellfun(@(xIn,zIn) plot(xIn,zIn,'-blue'),xNew,zNew)
Kind regards,
Robert