function demofunfun
% DEMOFUNFUN demonstration of function functions
disp('Starting demo of function functions...');
name = input('Enter the name of a function as a STRING: ','s');
% example: user enters 'cos'
plotf(name,linspace(-10,10,10000));
  
function plotf(name,x)
% evaluate the function with name NAME with input X
% FEVAL evaluates a function with given inputs
y = feval(name,x);
% we could also use less efficient EVAL(STRING) which
% evaluates STRING as a script command

% now plot the values:
plot(x,y);