function cf=getcf(pf) 
% getcf(pf)  generates a cumulative function from a pmf or pdf 
if ispf(pf)==0 
   error('invalid probability function') 
end 
x=xvals(pf); 
p=pvals(pf); 
newp=zeros(length(p), 1); 
P=0; 
if isdiscrt(pf)==1 
   for i=1:length(x), 
      P=P+p(i); 
      newp(i)=P; 
   end 
else 
   for i=1:length(x)-1, 
      dx=x(i+1)-x(i); 
      P=P+(p(i+1)+p(i))*dx/2; 
      newp(i+1)=P; 
   end 
end 
cf=[pf(1,1) 0; x' newp];