Entering a formula by user

Is there a function which allows me to ask for a formula, while the prgram is beeing used, and subsequently use that formula?

Answer 1

[Nirmal]

Have a look at eval: http://www.mathworks.com/help/techdoc/ref/eval.html

aMatrix = magic(5);

expression = input('Enter the name of a matrix: ','s');
if (exist(expression,'var'))
    mesh(eval(expression))
end

[Karel]

thanks, yust what i needed